The albedo, a Latin term meaning whiteness, is in alchemy one of the phases of the Magnum Opus, following the nigredo phase. Symbolized by a white swan, it is called “whiteness,” or alternatively ablutio, purificatio, mundificatio, or fissatio. It involves the purification of the formless mass produced by nigredo, washing away impurities to prepare it for the subsequent rubedo. In chemical terms, it corresponds to distillation and metaphorically represents the liberation of the soul from the bonds of corporeality.
Characteristics of Albedo
Albedo allows the transformation of lead into silver, acting in the phase following the dissolution of matter and recomposing it into a higher synthesis, following the alchemical motto solve et coagula. It represents dawn and rebirth, sometimes symbolized by a woman or a white rose.
It is also assimilated to the element of water for its purifying significance and because the ultimate goal of albedo is the creation of a fluid or vital liquid with regenerative virtues, akin to mercury or quicksilver, known as the elixir of long life.
The three phases of the magnum opus: nigredo (blackening), albedo (whitening), and rubedo (reddening).
On a macrocosmic level, the white of albedo is associated with the Moon, an image of purity and femininity, and among metals, with silver.
Another planet typically alluded to in albedo is Venus, formerly called “Lucifer,” meaning the bearer of light, as it radiates the white of light and knowledge in contrast to the darkness of nigredo. Although Christ alone was capable of combining such knowledge with freedom, he was therefore called “verus Lucifer.”
In Christian alchemy, the albedo specifically refers to the Resurrection of Jesus after the Passion and the sacrifice on the cross. Another allegorical episode of the albedo is the Baptism in Jordan, characterized by the descent of the white Dove. Venus, as the soul, is also an archetype of love, beauty, and creativity, serving as a bridge between the dark condition of the ego and the opening to higher dimensions of the spirit.
Albedo in Christian alchemy.
The alternation of white with black is often present on the entrance floor of Masonic temples, paved with white and black squares like chessboards, reminding us of the duality of light and darkness, spirit and matter, benevolent and malevolent powers. In the Divine Comedy, the albedo phase corresponds to the ascent through Dante and Virgil’s Purgatory. Alchemists attributed the phlegmatic humor to the albedo.
In the realm of analytical psychology, Jung likens the albedo to the revelation of the archetype of the anima in men and the animus in women. According to Jung, the individual, after becoming aware of the negative aspects of their own Shadow, has learned not to project them outward but to constructively engage with them.
This involves moving away from unconscious identification with the undifferentiated collective psyche and consciously turning inward through reflection in the process of self-individuation. Ultimately, the albedo entails the distillation of the ego from the unconscious.
The Latin term “rubedo,” which can be translated as “redness,” signifies in alchemy the final phase of the Magnum Opus, the reddening, following the nigredo and the albedo: it is the ultimate completion of chemical transmutations, culminating in the creation of the philosopher’s stone and the transformation of base metals into gold. While the nigredo involved putrefaction and albedo distillation, the rubedo occurs through sublimation under the influence of fire, that is, the Spirit. It is symbolized by the phoenix or a pelican, an egg, a red rose, or a crowned king.
Characteristics of Rubedo
Since red is considered by alchemists as the intermediate color between white and black, between light and darkness, the rubedo represents the reunion of opposites, the closing of the circle, the union of spirit and matter, masculine and feminine, or Sun and Moon, ultimately the androgynous or rebis. After lead has been transmuted into silver, it marks the final transition to gold.
Similarly, just as the nigredo corresponded to the alchemist’s physical body, and the albedo to their soul, the rubedo now identifies their spirit, the highest part of the three constituent organs of the human being.
The three phases of the magnum opus: nigredo (blackening), albedo (whitening) and rubedo (reddening).
The alchemist’s ultimate task at such a stage of development is not only to rise above matter but also to reunite with it and redeem it after making it fertile and purified from coarse aspects. Their soul, having liberated itself from corporeality, must also die to make way for the descent of the spirit, achieving the fusion of the Self with the world.
This is akin to the initial stages of the Magnum Opus but now consciously, at a higher level of awareness, and as a result of their free will. The Self becomes an instrument of God, realizing that it is one with the world and reflecting in it—the microcosm has become the macrocosm. In Christian alchemy, the color red is equivalent to Pentecost, the descent of the Holy Spirit to Earth in the form of tongues of fire.
On a planetary level, rubedo is associated with the Sun, symbolizing fire, and the Spirit, an astral body believed to govern gold, in which the Earth is destined to reunite in the future at the end of its evolution. The meaning of red, on the other hand, refers to blood, life, fertility, and sacrifice. It symbolizes sulfur reuniting with mercury, imparting its own dye—a term in alchemy that not only involves “painting” but specifically “transmuting.”
An old king in a closed flask representing rubedo. Apollo is riding the clouds in a chariot holding the Moon in his hand.
Red is also the attribute of the highest degrees of the Masonic hierarchy, and the color of the upholstery in lodges where its rituals take place. The prevalence of red is found in many national flags. For instance, Goethe considered red the quintessential color, a synthesis of opposites that “contains, in act or in potency, all other colors,” capable of giving an impression of both gravity and dignity, as well as clemency and grace.
In the Divine Comedy, rubedo corresponds to Dante and Beatrice’s entrance into Paradise. In the context of humor theory, the sanguine temperament is attributed to rubedo, or the choleric temperament.
Similarities Within a Psychoanalytic Framework
In the realm of analytical psychology developed by the Swiss psychiatrist Carl Jung, rubedo represents the archetype of the Self attained at the culmination of the individuation process. This is when the fusion between the ego and the Self occurs, symbolized by a red man and a white woman.
It signifies the union of opposites, the point at which the individual not only reclaims the unconscious material that had been deceptively projected outward but consciously reworks it at a higher level, opening up to love. In this way, one comes to discover their true nature, receiving the manifestation of the Self in its entirety.
Throughout its thousand years of history, various languages were spoken and/or written in the territories of the Eastern Roman Empire (or “Byzantine Empire”). Some languages evolved, others disappeared, many left written records, and all are mentioned in historical sources.
Scholarly Languages in Byzantine
The Empire had two official languages: popular Latin and medieval Greek (Μεσαιωνική Ελληνική). Latin was gradually abandoned by the elites around the 7th century but evolved into Italic Romance languages in Roman Italy and Balkan Romance languages in the lower Danube basin.
Widely understood, medieval Greek became prevalent in the East, where scholars wrote and could also express themselves in Koinè, the Greek language of the Hellenistic period, which has since become literary and scholarly. The Eastern Church initially used liturgical Greek (Ακολουθιακή Ελληνική) and later, in the Balkans, liturgical Slavic, employing the Cyrillic alphabet created for the Slavs by Cyril and Methodius. In Anatolia, the church used liturgical Greek and Armenian, whose alphabet is inspired by both Greek and Aramaic.
However, the diverse populations and various religious denominations in the Empire spoke many other languages, most of which had their own literature and contributed to conveying the tales, legends, knowledge, and debates of their time.
Common Languages in Byzantine
Common Greek
In Constantinople, along the coasts of the Balkan Peninsula and Anatolia, in Calabria, east of Sicily, and across all the islands of the Eastern Mediterranean, common Greek (Μεσαιωνική δημοτική), derived from the Attic Koinè, has always dominated, but with variations: Italic (Κατωιταλιώτικα) in Calabria and Sicily, Hellenic in the Balkans, around the Aegean and the Propontis, Micrasiatic in central and southern Anatolia, Notic in Cyrenaica and Egypt. To these variations, two dialects with Doric traits, also stemming from Koinè, should be added: Pontic around the Black Sea and Tsakonian in the Peloponnese.
Hellenist linguists debate whether the current varieties of modern Greek stem from medieval varieties (which presuppose a continuity of Greek settlement in place, a dominant hypothesis in Greek historiography) or only from Μεσαιωνική δημοτική (“common Greek”) Hellenic (which presupposes a more modern repopulation from Greece, a dominant hypothesis in Turkish historiography).
Byzantine Empire, c. 1180, at the end of the Komnenian period.
Demographers emphasize that one does not exclude the other, as under the pressure of military, economic, and environmental events, population movements have not ceased throughout history without the newcomers necessarily eradicating previous settlements (and their dialects). After the gradual settlement of the Turks in Anatolia in the 11th century, a Greco-Turkish dialect, Καππαδοκική Ελληνική / Cappadocian, developed in the Sultanate of Rum, whose name literally means “Sultanate of the land of the Romans,” also known as the “Sultanate of Iconium” and, in Turkey, the “Seljuk Sultanate of Konya.”
Anatolian, Iranian, Thracian, and Illyrian Languages
These are Indo-European languages spoken in the interior of the Balkans and Anatolia. In the Balkans (which were not yet called that; the word “Balkan” meaning “rocky slippery” is Turkish), Thracian and Illyrian languages were spoken, which later evolved either into Albanian dialects (Gheg, Tosk) or, through Romanization, into Vlach dialects north of the Jireček Line and, through Hellenization, into Greek dialects south of it.
In the interior of Anatolia, besides the numerous Greek enclaves in cities, various Indo-European languages such as Phrygian, Thynian, or Bithynian (Thracian languages) and dialects descended from ancient Isaurian and Cappadocian (Indo-European languages claimed by present-day Kurds as proto-Kurdish but linguists classify them in the Anatolian family, not the Iranian family from which Kurdish originates) were spoken. It’s crucial not to confuse Anatolian Cappadocian with the later Greek Cappadocian that emerged after the arrival of the Turks. Sarmatian, Roxolani, and Alan mercenaries in the army also used Iranian languages.
Romance Languages
Byzantine studies, focused on the shift from Latin to Greek as the official language, often overlook the Romance component of the Byzantine Empire. However, in Byzantine Italy, Sicily, North Africa, or the Byzantine part of Hispania, Romance languages were spoken, as well as in the interior of the Balkan Peninsula, where the Romanization of Illyrian and Thracian languages, respectively, produced Dalmatian and Eastern Romance (mentioned by Theophylact Simocatta and Theophanes the Confessor), the origins of Eastern Romance languages. The Byzantine Papacy, in particular, perpetuated the use of not only liturgical but also epistolary and civil classical Latin, also employed by scholars like Cassiodorus.
Later, starting in the 13th century, the colonies of Venetian and Genoese merchants established in Constantinople and other Byzantine ports spoke the corresponding dialects of northern Italy.
The annexation of the Ionian Islands and numerous Aegean islands (including Euboea, Crete, and Cyprus) by the Venetians imposed Venetian Italian as the lingua franca in these islands, leaving numerous place names and expressions in the local Greek language. Finally, the Latin Empire of Constantinople and the Latin states in the East established by the Crusaders in Greece promoted the use of medieval French and, in central Greece, Catalan in the armies and Latin colonies.
In popular Greek, the Latins are also indiscriminately called Franks (Φράγκοι): a designation more religious than linguistic.
Slavic and Turkic Languages
The flag of the Gagauz (Gök-Oğuz) people of Turkic origin.
From the 6th century onwards, Slavic languages (such as Sorbian, which contributed to the emergence of Serbo-Croatian, and Slavic) were added to the indigenous languages of the Balkans, as well as the Iranian-Turkic languages of the early Bulgars (a nomadic people from the Pontic steppe adhering to Tengriism, who adopted Slavic and Christianity) and the Gök-Oğuz (claimed by the present-day Gagauzes). In Anatolia, starting in the 11th century, the Turks began to settle, Turkify, and Islamize their inhabitants; initially, they wrote their languages in the Greek alphabet.
Additionally, many mercenaries of the Empire, including Antes or Khazars, were speakers of Slavic or Turkic languages.
Armenian and Caucasian Languages
In eastern Anatolia, from Cilicia to the Black Sea (which was not yet called that; this name is from Turkish, and the sea was then called the “Pontus Euxinus”), Armenian (another Indo-European language) and Laz, similar to modern Georgian, dominated. Literary and liturgical Armenian was also present elsewhere in the Empire, where Armenian communities lived.
Languages of East and North Africa
The Southeast (Syria, Canaan, and the extreme Northwest of Arabia) of the Byzantine Empire was the domain of various Aramaic dialects, including Syriac from Edessa (the language of communication and liturgy for the Semitic Christians of the region), Mandaic dialects, and various versions of Neo-Aramaic. In cities, these dialects coexisted with medieval Greek. In Egypt, the vernacular language was Coptic, derived from ancient Egyptian.
From the 8th century, after the intense Perso-Byzantine and Arabo-Byzantine wars, the long-standing Greek influence in the southeast of the Empire (for a millennium, in some places) and Latin influence in North Africa (for over six centuries) were erased. The Semitic populations (Syrians, Canaanites, Nabateans, etc.) and North Africans in the broad sense (the Egyptians and those commonly referred to today as Berbers) underwent linguistic and cultural Arabization and gradually became minorities among the Islamized Arabic speakers.
In contrast, Hellenistic Judaism persisted for another thousand years through the “Byzantine Jews,” who spoke Yevanic, following the Jerusalem Talmud, and whose synagogues continued to use Hebrew in the liturgical context. They were gradually assimilated first by the Arab Jews of the East and later by the Sephardim from the Iberian Peninsula, transitioning to the Babylonian Talmud, Ladino liturgy, and Judeo-Spanish language. A minority eventually became Turkish-speaking and Muslim, and a few Greek Jews remain in the 21st century after the majority of the community was annihilated during the Holocaust.
Other Languages
From the 10th century, Varangian mercenaries, of Scandinavian Germanic origin, also served in the Byzantine forces; it is likely that one of them engraved the runes visible on the current Byzantine lion at the entrance of the Arsenal of Venice. Finally, some law enforcement forces with multiethnic recruitment, such as the Vardariots or Vardariotai (Βαρδαριῶται), may have spoken Iranian, Finno-Ugric, or Turkic languages.
There are several customs observed around Christmas in England. Typically, the goal is to have all of the Christmas decorations taken down by the end of January 5th, which is the 12th day of Christmas. Christmas card sending has been around in England since 1843. The season begins with Christmas TV commercials, especially those from John Lewis and Aldi. One way to experience European Christmas customs is at a Manchester Christmas market. Typical English holiday fare includes turkey for lunch, mince pies, and Christmas pudding. At Christmas feasts, parties, and brunches, crackers are a great way to liven things up, and carol singing is another well-liked custom in the country.
Various greenery and other festive goods have been a part of Christmas traditions for generations in this country and the following are examples of traditional Christmas decorations that are quite popular:
Christmas Trees: Popular since the Victorian era, common evergreens include pine, spruce, and fir, and it is often thought that Thomas de Grey planted the first Christmas tree in England at Wrest Park in Bedfordshire in 1856. Many English houses choose to use real candles on their trees.
Holly, Ivy, and Mistletoe: The English have adorned their Christmas trees with evergreens like holly, ivy, and mistletoe for generations, and the holly represents Christ’s crown of thorns, while the ivy represents everlasting life. They hang mistletoe in front of doors to kiss beneath it.
Kissing Boughs: Kissing boughs are made of two or four interlocking hoops to create a sphere and during the Christmas season, they were strung in houses and embellished with evergreens.
Christmas Wreaths: Evergreen sprigs, holly, and other ornamental foliage make up a traditional English Christmas wreath. They are displayed at entrances.
Christmas Crackers: Including paper crowns in Christmas crackers is a custom with history in England. These are colorful paper encased in little cardboard tubes that hold a tissue paper crown-shaped hat, a tiny toy, a plastic model, or a trinket, as well as a little sheet of paper with a slogan, a joke, or a puzzle.
Christmas Traditions in England
Around 46% of the English and Welsh population identify as Christian. More than 90% of the population celebrates this day, but despite that, around 80% of them don’t see Christmas as a religious day. Many events, such as midnight church services and carol singing, mark the beginning of Christmas in England.
One English custom with deep historical roots is the King’s Christmas broadcast (or Queen’s). It started in 1932 when King George V aired it on the Empire Service of the British Broadcasting Corporation. Many people in Britain and beyond look forward to this speech every year on Christmas Day, including the Commonwealth residents. These broadcasts usually address the current events. King Charles III is the first reigning king to carry on the custom of giving the Christmas greeting as he delivers his annual Christmas address at 15:00 GMT on December 25.
Midnight Church Services
Church services at midnight, often called Midnight Mass, are an important tradition and on Christmas Eve, at around midnight, there is a special service held when people gather to honor the birth of Jesus. The clergy and choir of St. Martin-in-the-Fields, a London church, and others around the country celebrate this activity.
Another Christmas custom is singing carols, which entails gatherings of people in public spaces or going door to door to sing traditional songs. Renowned for their renditions of Christmas hymns and teachings, the choirs of Hampton Court Palace’s Chapel Royal and the Saint Church create a nostalgic ambiance.
The Royal Family’s Christmas Traditions
Going to the Sandringham Estate every year to celebrate Christmas is a royal family tradition in England. In observance of their German background, they celebrate Christmas Eve with present exchanges, black-tie banquets, and pick-up games of football and charades. The great-grandchildren assist in the decorating of the dining room’s Christmas tree and a gigantic silver artificial tree at Sandringham, and the family also attends a black-tie dinner on Christmas Eve.
Members of the King’s household also send out yearly Christmas cards and they exchange gifts after teatime on Christmas Eve after setting out their presents on trestle tables. St. Mary Magdalene Church at Sandringham, which dates back to the 16th century and was visited by Queen Victoria, is the location of the family’s Christmas morning ceremony.
Along with these customs, members of the royal family are known to be generous donors to nonprofits. They host Christmas parties to raise money for organizations. The royal family sends Christmas trees to Westminster Abbey, St. Paul’s Cathedral, St. Giles’ Cathedral, and Edinburgh’s Canongate Kirk.
Other Customs
Various events take place during the Christmas season in England, besides church services and the singing of carols. Town and village festivals, Christmas concerts, and seasonal festivals are all possibilities. Every year at the Royal Albert Hall in London, hundreds of carolers gather for “Carols at the Royal Albert Hall.” Smaller towns and villages also have old-fashioned Christmas markets and festivities, complete with medieval feasts, Tudor Christmases, and Victorian-era parties.
Traditional Christmas Foods in England
Making the Empire Christmas pudding. Artwork by F C Harrison.
Christmas dinners include delicacies that have been passed down through generations. These are the main ones:
Roast Turkey: For many British families, the main course of Christmas dinner is roast turkey. Common accompaniments include stuffing, gravy, and cranberry sauce.
Christmas Pudding: Traditional ingredients for Christmas pudding include suet, dried fruit, and spices; the result is a thick and decadent fruit pudding. It goes with custard or brandy butter.
Mince Pies: Sweet little pies packed with suet, dried fruits, and spices are called mince pies, which are served with a dollop of brandy butter. They are a beloved Christmas delicacy.
Yule Log: A classic Christmas dish, the Yule Log is a rolled sponge cake filled with chocolate buttercream and topped with a chocolate buttercream icing. Serving it with a sprinkling of icing sugar makes it appear like snow, and decorating it to look like a log is common.
Pigs in Blankets: Little sausages encased in bacon and cooked till crisp make up pigs in blankets. They go with roast turkey and are a staple holiday side dish.
Bread Sauce: The classic combination of bread, milk, and spices yields this velvety sauce. Pair it with roasted turkey or another roasted meat for a typical Christmas meal in England.
Cracker jacks with their paper crowns are always a good time at the dinner table. Nowadays, people utilize little cardboard tubes covered in brightly colored paper as Christmas crackers. Inside are colored tissue paper crowns, little toys, plastic models, or trinkets, and a piece of paper with a proverb, joke, puzzle, or information.
In the United Kingdom, Christmas crackers have been a holiday ritual since the Victorian period. A confectioner from London named Tom Smith manufactured these in the 1845–1850 and the paper crown was an afterthought. The first crackers just included a brief phrase or riddle. The paper crown tradition has its roots in the ancient Romans’ use of headdresses for the December celebration of Saturnalia.
The custom of crowning oneself with a paper crown may have also arisen during the Twelfth Night festivities, when a monarch was chosen to preside over the events. At Christmas dinner, people wear paper hats that look like crowns. It is said that the practice of wearing celebratory headwear originated during the Saturnalia celebration in Roman times, when participants wore paper hats.
History of Christmas in England
Saint Nicholas.
Since the introduction of Christianity, Christmas has been celebrated in England, and the earliest known date of Christmas in England was when Augustine baptized 10,000 Saxons in Kent on Christmas day in 597. The Middle Ages were a time of somber and magnificent Christmas festivities, when monarchs would host lavish feasts and organize Christmas courts. It was in the nineteenth century that many of the modern-day Christmas traditions—including Christmas trees, greeting cards, and even Father Christmas—came into being.
It wasn’t until 1848, when Queen Victoria married Prince Albert of Germany, that Christmas trees really took off in England. The tradition had been around since the early 1800s. On the other hand, the first practice of kissing beneath the mistletoe was documented in 1784. St. Nicholas (a Christian bishop from Turkey in the fourth century AD) is believed to have been the inspiration for both Father Christmas and the Dutch Santa Claus, who became one in the nineteenth century.
Saint Nicholas and Twelfth Night Cake
Saint Nicholas celebrated his feast day on December 6th, and he is famous for distributing presents and it was in the late 19th century that the custom of eating Twelfth Night cake at Christmas first appeared in England. Historical events and religious beliefs have shaped Christmas festivities in England. For instance, from the mid-1640s to 1660, Christmas was outlawed in England, Wales, and Ireland due to the Puritan period.
On the other hand, the Parliament designated the last Wednesday of the month as a “fasting day” in 1644 so that people could reflect somberly on their transgressions. Christmas didn’t become popular again in England until the nineteenth century, when the royal family took the lead in instituting customs that are still practiced today.
Early Christians in England incorporated pre-Christian midwinter practices into their own Christmas celebrations after the arrival of Christianity. In 601, Augustine was ordered by Pope Gregory the Great to include these practices in Christian festivities. The English adopted several pagan customs for their Christmas festivities, including the usage of mistletoe, the Yule log, and the custom of keeping an evergreen tree inside the home. Christmas trees, greeting cards, and the arrival of Santa Claus have developed over the years and drawn inspiration from a wide range of historical practices.
Byzantine science and technology played a significant role in preserving knowledge from classical antiquity and transmitting it to the Arab world and Western Europe towards the end of the Middle Ages and the beginning of the Italian Renaissance. With a few exceptions, especially in the military domain, the Byzantines showed little innovation, both in scientific pursuits, focusing less on the theoretical aspects of sciences like mathematics or astronomy and more on their practical applications, and in technology, where they perpetuated techniques used in the Roman Empire.
During that time, the concepts of science and technology differed greatly from what they are today. Sacred texts and philosophy were as much a part of it as mathematics and astronomy (high science) or astrology and alchemy (low science). In history, Universal Chronicles, widely popular in the Middle Ages, aimed primarily to demonstrate the role played by the Empire in the divine plan, while Histories served less as an objective account of past events and more as an apology for a prince and his family. The divisions between sciences were not rigid, and intellectuals could teach both medicine and philosophy.
Therefore, categorizing a scholar into a specific field often reflected their primary area of expertise.
Science in Byzantine
Michael Psellos (left) with his student, Byzantine Emperor Michael VII Doukas.
Byzantine scientific production showed little notable progress compared to that of classical antiquity, from which it drew its sources. Nevertheless, it had the advantage of preserving and transmitting this knowledge to the Muslim world and the Europe of the Italian Renaissance. It relied on philosophy and metaphysics, supplemented by history, geography, mathematics, and astronomy. Despite some opposition to pagan tradition, many classical scholars, such as Michael Psellos or John Mavropous, held high positions in the Church.
The writings of antiquity continued to be studied in the Byzantine Empire, thanks to the emphasis on classical studies by the Academy of Athens in the 4th and 5th centuries, the vitality of the philosophical academy of Alexandria, and the growth of the University of Constantinople, where only secular subjects were taught, with theology being taught at the Patriarchal Academy. Monastic schools focused on the Bible, theology, and liturgy.
Monastery scribes concentrated on reproducing religious manuscripts, while works of pagan antiquity were transcribed, summarized, and annotated by civilians or clergy members like Photios, Arethas of Caesarea, Eustathius of Thessalonica, and Bessarion. The distinction between various sciences or their interrelation was much less rigid than today, and many scholars were polygraphers who wrote on diverse subjects. For example, in the early 12th century, Michael Italikos simultaneously taught sacred texts, mathematics (arithmetic, geometry, astronomy, and music), mechanics, optics, medicine, and philosophy.
History
In Byzantium, history takes two forms: either the description of events during a reign or a period, usually written to glorify a prince or a family, or a universal chronicle whose purpose is to convince the reader that the Byzantine world and the Orthodox faith, under the emperor’s guidance, reproduce on Earth the order desired by God in the heavens. While the former are written in a polished and sophisticated style, the latter are written in a language not far from everyday speech.
An example of these universal chronicles is the one written by John Malalas (c. 491–578), a Syrian rhetorician of the 6th century and an official of the imperial administration. In his Chronographia, he recounts the history of the world from creation to “Emperor Zeno and the emperors who followed him.”
Historia Chronica. John Malalas.
It would be impossible to enumerate all the Byzantine historians here.
Let’s mention that, across the centuries, only the Byzantine historiographer Theophylact Simocatta, considered the last historian of the ancient world, lived in the early 7th century. He wrote a historiographical work titled Histories, following the historians of the 6th century (Procopius of Caesarea, Agathias of Myrina, and Menander Protector), narrating the reign of Eastern Emperor Maurice I (582–602). It constitutes an essential source of information on the Persians and the Slavs. Theophanes the Confessor (c. 758–818), aristocrat, monk, theologian, and chronicler, is primarily known as the author of an important Chronographia, continuing that of George Syncellus (died after 810) from Diocletian to the fall of Michael I Rangabe.
In the 11th century, George Kedrenos, known as Kekaumenos, wrote a Universal Chronicle that, as was customary at the time, spans from the creation of the world to the accession of Isaac Komnenos (1057). It is one of the few sources on the cities of Khazaria after the sack of Itil (or Atil) in 969. The first child of Emperor Alexios I, Anna Komnene (1083-1153), wrote the Alexiad around 1148, an apologetic work dedicated to her father but also containing information on the Normans, Scythians (Pechenegs), and Turks, in addition to providing a Byzantine perspective on the history of the First Crusade.
In the same century, John Skylitzes (circa 1040–early 11th century) authored the Synopsis Historiarum, a chronicle covering the period from 811 to 1057 (Amorian and Macedonian dynasties). It aims to be a continuation of the Chronographia by Theophanes the Confessor. In addition to transmitting historical knowledge from antiquity, many of these authors, building on the works of ancient authors, some of whom are known only through them, add data on the more recent world up to their respective times.
Geography
Constantine VII as sole emperor, 945–959.
Byzantine geography was based on the works of Strabo (circa 60 BC–20 AD) and Pausanias (circa 115–180). It primarily involved descriptive geography with an economic purpose, with theoretical geography being almost entirely overlooked. For instance, the Periplus of the Erythraean Sea, written in Greek between the first half of the 1st century and the 3rd century, is a narrative of maritime exploration describing navigation and commercial facilities from Roman-Egyptian ports like Berenice along the Red Sea coast, following the maritime route along the coasts of East Africa to India.
The same utilitarian goal is evident in the work of Constantine VII (effective rule 944-959), De administrando Imperio (“On the Administration of the Empire”), where the emperor describes, for his son’s benefit, the countries and peoples surrounding the empire (Serbs, Croats, Rus’, Pechenegs, etc.), the routes through which they come into contact with Byzantium, and the means to form alliances with them against enemies (Khazars). A similar approach is found in the numerous reports of Byzantine ambassadors to foreign lands, such as Priscus (5th century) (on the court of Attila), Nonnosus (6th century) (on the region of the Red Sea), and Theodore Metochites (1270–1332) (on Armenia and Serbia).
Cartography replaced the description of countries and cities with lists of names, as seen in the Synecdemus of Hierocles, a 6th-century catalog of nine hundred cities of the Byzantine Empire classified in approximately geographical order across sixty-four provinces. These works were often influenced either by the Byzantine cosmological vision of the world, as seen in Cosmas Indicopleustes (6th century), whose description of the world, titled Christian Topography, rejected the image of the world held by Greek scholars, deeming it incompatible with the teachings of the Bible, or by the uncritical acceptance of sources, as seen in Constantinople Porphyrogenitus’ De Thematibus, where the distribution of cities in ancient times would be identical to that of the 10th century, or by folklore information found in various descriptions of countries and their peoples.
Mathematics and Astronomy
In Byzantium, mathematics and astronomy were inseparable and jointly formed what is commonly referred to as the “high” scientific tradition, as opposed to the “low” tradition, which included alchemy and astrology. This tradition was based on the works of Euclid (3rd century BC), Archimedes (2nd century BC), and Ptolemy (1st century BC). John Philoponus (5th century) is likely the one who bridged the gap between Hellenistic and Byzantine science. A grammarian, philosopher, and Christian theologian, he wrote the earliest treatise on the planispheric astrolabe and its uses. Also during the time of Justinian I, Eutocius of Ascalon, a Greek geometer and author of commentaries on the writings of Archimedes and Apollonius of Perga, introduced Greek mathematics to Constantinople.
The two architects of the Hagia Sophia in Constantinople, Anthemius of Tralles and Isidore of Miletus (6th century), were particularly known, the former as a mathematician specializing in the study of parabolas, and the latter for overseeing the publication of Archimedes’ treatises on the measurement of the circle, spheres, and cylinders.
In the 7th century, Alexandrian science, where astronomy and mathematics held a prominent place, migrated to Constantinople. Stephanus of Alexandria (around 550–after 619) wrote a treatise on astronomy titled “Explanation of Theon’s Tables by Specific Examples,” connecting him to the “high science,” while various alchemy treaties preserved under his name linked him to the “low science.”
Leo the Mathematician.
A new era began in the 9th century with Leo the Mathematician, a Byzantine scholar, philosopher, and religious figure who revived mathematical sciences, astronomy, and natural sciences. He played a crucial role in having the major works of ancient mathematicians such as Euclid, Diophantus, Apollonius, Ptolemy, Archimedes, and others copied.
At the end of the first millennium, the “Macedonian Renaissance” (867-1056) would further develop the earlier Greek achievements, continuing the lineage of “commentators” while incorporating the scientific advancements of the Arabs and Persians, of which the Byzantines became experts. This penchant for transcribing ancient works continued until the 12th century.
During the reign of Manuel I Komnenos (r. 1118–1180), an avid enthusiast of astronomy and astrology, Ptolemy’s “Treatise on Astronomy” was translated in Sicily, likely by Adelard of Bath. It is possible that it was from Italy that the Byzantines received Arabic numerals in the 12th century, which took a long time to spread. George Pachymeres (1242–1310), better known as a historian, was acquainted with them when he wrote his “Manual of the Four Sciences.”
After a period of decline, interest in mathematics revived with Theodore Metochites (1270–1332), a statesman and intellectual who wrote an introduction to Ptolemy’s astronomy, a treatise on the mathematical form of philosophy, and numerous commentaries on Aristotle. A staunch advocate of Ptolemaic theories, Isaac Argyros, theologian, mathematician, and astronomer, would write a treatise on the astrolabe in the following century, two books on astronomy, an essay on square roots, a scholia (a comment) on Euclid, and a new edition of the commentary on Nicomachus.
His contemporary, Theodore Meliteniotis (around 1320–1393), a high sacellarius (inspector of monasteries) and later, around 1360, director of the patriarchal school, wrote a treatise titled Three Books of Astronomy (Άστρονομική τρίβιβλος), making him the greatest astronomer of Byzantium alongside Nicephorus Gregoras (circa 1295–1360). Gregoras, however, is better known as a historian, thanks to his Roman History. Scientifically, his Treatise on the Astrolabe is preserved, and he was one of the first, since antiquity, to accurately calculate and predict the total solar eclipse of July 16, 1330.
From this period on, the works of ancient Greek authors left Constantinople with emigrants who settled in the West. Alongside those already translated into Arabic, Latin, or Hebrew, these works would contribute to a mathematical renaissance.
Physics
In this field as well, the Byzantines continued the work of the ancient Greeks by copying, teaching, or developing their ideas to reconcile Greek thought with Christian conceptions of the universe. Their significant merit, however, lies in transmitting this knowledge to the Syrians, Arabs, and, in the 13th century, to Norman Sicily. Similar to geography, their interest focused more on the application of physics to technical problems than on theory.
John Philoponus (also known as John the Grammarian—around 490–after 568), a philosopher and Monophysite theologian, challenged Aristotle’s theory that projectiles continue to move due to a driving force transmitted by the thrower (and not by the air’s push), replacing it with the theory of impetus. His critiques would inspire Galileo Galilei, who would cite him several times in his works.
Aristotle’s Physics continued to be studied in Constantinople until the 14th century, with abundant commentaries by Simplicius (around 480–509), Michael Psellos (c. 1017–1078), Michael of Ephesus (11th century), and Theodore Metochites (1270–1332). Michel Psellos, among others, contributed numerous works on matter, color, motion, echo, rain, thunder, and lightning. His contemporary, Simeon Seth, authored a five-book Treatise on Physics (on the earth, the four elements, the sky, matter and soul, and the final cause), inspired by Aristotelian principles.
In the realm of applied physics, General Belisarius (500–569) is credited with the invention or at least the implementation of the first “floating mills,” water mills installed on a boat in the course of a river or a stream. In 537, the supply of flour to Rome was interrupted during the siege of the Goths. Drawing on an idea from Vitruvius, a Roman engineer from the 1st century, Belisarius had these boats constructed, where instead of propelling the boat, the water was used to grind the grain.
Medicine
Much like in architecture, medicine is one of the sciences where the Byzantines surpassed their Greco-Roman predecessors and influenced both Arab-Muslim medicine and the development of medicine in Europe during the Renaissance. The works of Hippocrates and Galen formed the foundation of medical knowledge, enriched by scholars such as Oribasius (circa 325–395), a Byzantine compiler of medical knowledge who did not hesitate to correct faulty ancient methods; Aetius of Amida (6th century); Alexander of Tralles (6th century); and Paul of Aegina (7th century). Paul’s Collection of the Pleiades (in Greek: Epitomes iatrikes biblia hepta; in Latin: De Re Medica Libri Septem) is a compilation of seven books of texts from ancient physicians, foreshadowing the anthological approach of the tradition.
A renewed interest in medical treatises emerged in the 10th century with authors like Meletius the Monk (9th century), Theophanes Nonnus (10th century), Simeon Seth (mentioned earlier, 11th century), Nicholas Myrepsos (13th century), author of a treatise in 48 books containing 2,656 formulas for medicines composed from 370 plants, and Joannes Actuarius (14th century), whose three preserved works primarily deal with dietetics, hygiene, and medications. In addition to the knowledge acquired from the Greeks, the Byzantines added insights imported from the Arabs and Persians. Simeon Seth was the first to mention oriental products such as cloves, nutmeg, and hemp seeds. Myrepsos’s treatise, on the other hand, includes numerous recipes from Sicily or of oriental origin.
The particular attention given to hygiene and sanitary organization was a constant concern for the imperial administration and the Church, which was in charge, constituting an innovation compared to the Ancients. It inspired the establishment of hospitals, the training of physicians, and the preparation and preservation of medicines.
The first hospital was probably founded by Basil of Caesarea (329-379), a bishop who built a hospice in each district of his diocese to accommodate the poor and the sick. In Caesarea itself, he constructed a complete “hospital complex,” including, in addition to a church, a nursing home for the elderly, a hospital for the sick, an inn for travelers and pilgrims, accommodations for service personnel, and schools for the orphans of the city. Subsequently, services would “specialize.”
For example, the Pantokratoros Monastery founded in the 12th century had a hospital designed for fifty patients, men and women, distributed in five rooms (ὄρδινοι) of different sizes: a ward for the wounded with ten beds, one for patients with eye or abdominal ailments with eight beds, a room reserved for women with twelve beds, and two other rooms for ordinary patients. The staff consisted of specialist physicians, assistants, and pharmacists preparing medications.
Technology in Byzantine
Architecture
The field of architecture is likely where the Byzantines excelled in surpassing their predecessors. From Constantinople to the construction of the Basilica of Hagia Sophia under Justinian, it essentially continued the traditional Roman architecture where vast buildings were dedicated to worship or public affairs and could accommodate large crowds. Subsequently, especially during the period when monasteries multiplied and buildings tended to be used by a limited clientele (officials and dignitaries) rather than crowds, the structures took on more modest dimensions. Succeeding the oblong-shaped basilica-plan churches, the cross-in-square church, built from a naos forming a square in which the four arms of the cross fit, became the archetype of Byzantine Orthodox churches.
The center of the naos is usually surmounted by a dome. The Byzantines are credited with creating the “dome on pendentives,” with the first example being Hagia Sophia (563). While the dome was already known in Roman architecture, the use of pendentives allowed for considerable height and grandeur. After being employed in the plans of many Byzantine Orthodox churches, this style would be adopted in the construction of Muslim mosques.
In addition to the buildings dedicated to worship, Byzantine architecture developed with numerous civil structures. The Grand Palace of Constantinople, now in ruins, constituted the largest architectural complex in Constantinople. Constantly expanded from Constantine the Great until the 10th century, it formed a somewhat eclectic ensemble of administrative buildings, courtyards, pavilions, and churches, reminiscent of the Kremlin in Moscow. The walls of Constantinople, along with the Theodosian Wall, with their 12 miles in length and imposing towers, resisted all enemies for over a thousand years.
The water supply for the city, crucial during sieges, was ensured by vast cisterns, some underground, like the “Sunken Palace” (in Turkish, Yerebatan Sarayı). Initiated under Justinian in the 530s, this multifunctional structure housed an underground cistern measuring 452 by 213 ft, adorned with 28 rows of 12 columns each supporting a brick vault. In addition to the “Aqueduct of Justinian,” one can still admire the monumental bridge crossing the Sangarius River (now Sakarya), dating from the 6th century, as well as the bridge over the Karamagara in eastern Turkey, the first example of a pointed arch bridge. Dating from the 5th or 6th century, it is a single-arched bridge, 56 ft in length and 33 ft in height.
Military Technology
A Byzantine trebuchet and a Byzantine siege of a citadel. 11th century.
The most well-known Byzantine invention in the military field is undoubtedly Greek fire. Dating from the late 7th century, it is attributed to Callinicus of Heliopolis, an architect who sought refuge in Constantinople. Probably made from a mixture of pine resin, naphtha, calcium oxide (quicklime), sulfur, or saltpeter, Greek fire remained one of the most closely guarded military secrets, both in terms of its production and propulsion.
In his book “De Administrando Imperio,” Emperor Constantine VII instructs his son and heir Roman II never to reveal the secrets of Greek fire production, which were “shown and revealed by an angel to the great and holy first Christian emperor Constantine,” who swore “to prepare this fire only for Christians and only in the imperial city.” The secret was so well kept that when the Bulgarians seized a large quantity of the liquid and siphons needed for its propulsion, they proved unable to use it.
The liquid jet was heated and projected by a siphon from a bronze tube. It could burn on the water and could only be extinguished by sand, depriving the fire of oxygen, or with vinegar or old urine, probably due to a specific chemical reaction. Its use, especially against military fleets, had disastrous effects on the enemy and ensured the survival of the empire during the two Arab sieges of Constantinople (674-678 and 717-718).
Soon, the Byzantines discovered that Greek fire could also be projected using incendiary grenades, which appeared shortly after the reign of Leo III (717-741) in the form of containers made of stone or ceramic. These relatively large containers were launched at the enemy using catapults or trebuchets, either already aflame or ignited by a flaming arrow after their launch.
The traction trebuchet, a siege weapon also known as a mangonel, was already known in China in the 4th century BC. It spread to the West with the Avars and was adopted by the Byzantines in the 6th century. It used human force to propel projectiles towards the besieged walls. Its successor, the counterweight trebuchet, which uses a counterweight instead of human force, is probably of Byzantine origin and was first described by the historian Niketas Choniates when it was used by Emperor Andronicus I during the Siege of Zevgminon in 1165. However, it is not impossible that it had already been used by Alexis I, who, during the siege of Nicaea, is said to have invented new artillery pieces that were not of the conventional model and made a strong impression on the Crusaders, his allies.
Similarly, the portable trebuchet (in Greek: cheiromangana) consisted of a sling mounted on a support that used a lever to launch projectiles. It was used by Emperor Nikephoros II Phokas around 965 to disperse enemy formations in open terrain. It is also mentioned in the tactics of General Nikephoros Ouranos (around 1000) and classified as a form of war weapon in the anonymous work “De obsidione toleranda.”
Byzantine Relations with the Arab World
Cultural and scientific exchanges between the Byzantine and Arab worlds were numerous and frequent. Within the Abbasid Caliphate itself, there were monasteries and Christian communities where Greek literature spread throughout the 8th century. The caliphs attempted to attract certain Byzantine intellectuals, such as Leo the Mathematician (9th century), to Baghdad. Photios (9th century), then a professor in Constantinople and future patriarch of Constantinople, likely worked in Baghdad during the embassies he led in 838, 845, and 855.
The Byzantine Empire thus enabled the medieval Muslim world to acquire ancient and more contemporary Greek texts on astronomy, mathematics, and philosophy, which were then translated into Arabic. On the other hand, Byzantine scholars like Gregory Chioniades (early 13th century-early 14th century), who had visited the brilliant intellectual center of Maragha in Persia with its observatory founded in 1259 by Hulagu Khan, translated Persian astronomical tables into Greek, including Nasir al-Din al-Tusi’s Ilkhanate Tables, al-Khazini’s Sinjar Tables, and the tables and commentaries of his master Shams al-Bukhari. Other Byzantine scholars used transliterations of Arabic to describe certain scientific concepts rather than the traditional ancient Greek terms, such as the Arabic term “talei” instead of the ancient Greek “horoscopos.”
Byzantium played a significant role not only in transmitting ancient Greek knowledge to Western Europe but also in introducing Arab knowledge. According to some historians, Copernicus or any other European author might have had access to Arabic astronomical texts, particularly those related to the “Tusi couple,” an astronomical model mentioned earlier and developed in 1247 by Nasir ad-Din at-Tusi. This model presented a version of the geocentric model of the solar system that did not use Ptolemy’s equant point and would be adopted by Copernicus for the first version of his heliocentric model in 1543. It was also through Arabic scientific texts that Byzantine scholars became acquainted with Sassanian and Indian astronomical theories.
Byzantine Relations with the West
During the early Middle Ages, the Greek language was virtually unknown in the West. Only a few texts by Aristotle (part of the Organon thanks to Boethius) and the early Church Fathers survived. A shift occurred with the development of trade between the East and the West after the early Crusades. In the cities of northern Italy and later in Rome (where the papacy had re-established itself in 1420 after a long stay in Avignon) and in Venice (including its university city, Padua), the economic and political bourgeoisie of the time increasingly became interested in the heritage of the ancient Greeks and Romans and their political thought.
In southern Italy, a significant Greek community persisted in the 13th century, concentrated in the regions of Messina, Calabria, and Apulia. This community maintained its cultural identity through numerous contacts with Constantinople and its religious identity, both through its adherence to a liturgy distinct from the Roman liturgy and its recognition of the Patriarch of Constantinople as the true head of the Church.
The first to show interest in the legacy of ancient and Byzantine Greece were Italian scholars such as Petrarch (1304-1374) and Barlaam of Seminara (1290-1314), who combined Latin and Greek culture, managed to obtain original Greek texts or personally traveled to Constantinople to study Greek. After the sack of Constantinople by the Crusaders (which led to the disappearance of many ancient works) and the city’s recapture by Michael VIII Palaiologos, the empire, reduced to a confederation of city-states, witnessed an intellectual revival known as the “Palaiologan Renaissance.”
During this period, the Byzantines increasingly clung to their cultural roots, considering themselves heirs to the poets, philosophers, historians, and scientists of ancient Greece. One of the early representatives of this renewal was likely Nicephorus Blemmydes (1197–1269), who traveled through Greece in search of manuscripts for his teaching and wrote, among his numerous treatises, a manual on Aristotelian philosophy.
While Petrarch and Boccaccio had expressed the desire to learn Greek to read ancient texts, it was with the arrival of a Byzantine diplomat, Manuel Chrysoloras (circa 1355–1415), that this dream could be realized. After an initial trip to Italy in 1394 to seek Western aid against the Turks, Chrysoloras arrived in Venice in 1396 and settled in Florence the following year. During the three years he spent there, he taught Greek to several humanists, including Niccolò Niccoli and Leonardo Bruni.
Twenty years after Chrysoloras’s death, the Council of Florence convened to achieve the reunification of the Eastern and Western Christian Churches, facilitating the most significant encounter between Italian and Byzantine intellectuals of this pivotal period between the Middle Ages and the Renaissance. In November 1437, the emperor and a delegation of about 700 people, including Patriarch Joseph II, twenty metropolitans, numerous bishops, and theology-savvy laypersons, embarked for Venice.
Among them was Gemistos Plethon (c. 1355 or 1360 – June 26, 1452), known as Plethon by analogy with his idol, Plato. Little interested in theological debates, he spent most of his time lecturing on the philosophical differences between Plato and Aristotle, which fascinated the Florentines. His treatise defending Plato and criticizing Aristotle sparked a controversy that continued in Rome long after the council and Plethon’s return to Mistra, where he spent his final days. It was probably his activity that inspired Cosimo de’ Medici to establish the Platonic Academy.
One of his colleagues in the Byzantine delegation was Basilius Bessarion (1403-1472), who participated in the council with the pro-unionists and converted to Roman Catholicism at the end of the council. Rejected by his compatriots upon his return to Constantinople, he went back to Rome, where he had been made a cardinal, and brought many ancient manuscripts from Constantinople to protect them from the imminent Turkish invasion. These manuscripts were used, among others, by George of Trebizond, Theodorus Gaza, and perhaps Lorenzo Valla to translate and introduce several authors and Fathers of the Greek Church. His library, consisting of 746 manuscripts, was bequeathed to the Republic of Venice after his death, where, along with others, they would form the collection of the Biblioteca Marciana.
The fall of Constantinople to the Turks in 1453 caused the exile not only of numerous Byzantine intellectuals and university professors but also of a considerable number of individuals working in their circles, such as scribes or anonymous translators. These individuals played a role, often obscure but nonetheless essential, in the dissemination of Greek texts. Moreover, not only did these emigrated artists and craftsmen bring with them many previously unknown manuscripts to the West, but they also corrected often corrupted texts that had already reached the West, especially through various Arabic versions.
By collaborating with the Byzantine and Alexandrian commentators of Aristotle and Plato, they facilitated a better understanding of the original spirit of these texts. Finally, their collaboration with the emerging printing presses gave a new impetus to their teaching at various Italian universities.
Alchemy in the Byzantine world is part of a set of scientific practices inherited from ancient civilizations, such as the Greeks, Romans, Egyptians, and Mesopotamians, which Byzantine intellectuals studied, taught, and transmitted through scientific institutions like the University of Constantinople.
Historical Background
For ancient civilizations, alchemy was a coloring process used to modify objects, most commonly metals, to give them a new value. The modification is achieved using dyes or chemical elements. Ancient alchemy was also a way to express the mystical nature of the world and was often combined with philosophical, religious, or astronomical studies. This perspective on ancient alchemical practice was passed down to Byzantine scholars, for whom scientific practice was more about preserving and studying the great works of antiquity than introducing new developments. For example, the writings of Greek philosophers such as Plato, Aristotle, and Democritus held great importance in Byzantine scientific discourse.
Generalities of Byzantine Alchemy
Alchemy played a significant role in the work of Byzantine scientists, who often held ecclesiastical positions as well. For Byzantine intellectuals, alchemy represented a meeting point between the scientific and spiritual domains. Alchemy in the Byzantine world cannot be separated from philosophy, rhetoric, astronomy, astrology, and religious studies. Byzantine science is primarily known for sharing the scientific knowledge of ancient thinkers with other civilizations of their time, such as the Muslims or, following the fall of Constantinople, with the great thinkers of the Italian Renaissance. In this sense, Byzantine alchemists played a key role in the development of alchemy across Europe and the Middle East.
Precursors of Alchemy in the Byzantine Empire
Texts from the 4th Century
Two of the earliest precursor texts of Byzantine alchemical practice are manuscripts that belonged to the Greek merchant Giovanni Anastasi in the 18th and 19th centuries. They were respectively transmitted to the Museum of Leiden in the Netherlands and the Kungliga Biblioteket in Stockholm. These two texts, likely originating from the Egyptian scientific tradition and dating back to the 4th century, compile several recipes related to the transformation of silver, gold, gemstones, and fabrics. They align with the so-called pseudo-Democritean tradition, stemming from the materialistic ideas of the Greek philosopher Democritus.
These texts represent some of the earliest tangible examples of alchemical recipes that reached the Byzantine world and precede other foundational texts for Byzantine alchemical works, such as those of the Greco-Egyptian alchemist Zosimos of Panopolis.
Zosimos of Panopolis
The works of Zosimos of Panopolis go even further by establishing a connection between the transmutation of metals and religious practice. Zosimos’ works also depart from simple recipes to describe much more complex chemical processes. According to Zosimos’ writings, all substances are composed of a body (soma) and a volatile part (pneuma), attributable to their spirit.
Alchemical practice, according to Zosimos, is essentially a process seeking to use fire, either through distillation or sublimation techniques, to separate the spirit from the body. This concept would have a significant influence on Byzantine and Arab philosophers in the following centuries, and Zosimos can be considered the first major philosopher in the Byzantine tradition.
Stephanus of Alexandria and the School of Alexandria
Cherub and Heraclius receiving the submission of Khosrow II. 1160–1170, Paris, Louvre.
The beginning of the 7th century witnessed the emergence, in the realm of alchemy, of a circle of Alexandrian thinkers commonly referred to as the School of Alexandria, or the Philosophical Academy of Alexandria. This school encompasses several great thinkers, including Stephanus of Alexandria, an alchemist, mathematician, philosopher, and astronomer. Stephanus of Alexandria was one of the first Alexandrian thinkers to export his ideas to the Byzantine world, following an invitation to the court of the Byzantine Emperor Heraclius around the year 610.
Stephanus of Alexandria and his compatriots, such as Olympiodorus the Alchemist, Synesius of Cyrene, and Aeneas of Gaza, dedicate themselves to the study of Greek, Roman, and Egyptian alchemy and philosophy. Synesius is notably credited with a commentary on the pseudo-Democritean writings dating back to 389, and Olympiodorus with a commentary on the works of Zosimos. Stephanus of Alexandria, on his part, provides several commentaries on the works of Plato and Aristotle, along with a mystical treatise on the transmutation of metals into gold. Commenting on Greek alchemical works, he asserts:
“The wise speak in riddles as much as possible… Material furnaces, glass instruments, bottles of all kinds, alembics, and kerotakis [a metal plate placed on a container with burning coals to melt the wax and condense vapors]—those who attach themselves to these vain objects succumb under this tedious burden.”
For him, alchemy was more of a mystical pursuit than a scientific one, dissociating itself from the material aspect of alchemy, which he defines as “the systematic study of the creation of the world through the word.” His works consisted of revisions of atomic concepts from the ancient era, such as the Stoic model wherein the spirit is composed of air and fire and has the ability to penetrate every element of the world and govern it.
The spiritual aspect is an integral part of Stephanus of Alexandria’s work, illustrating the strong connection between sciences like alchemy and the ecclesiastical profession in the Byzantine Empire. Indeed, religious congregations and monasteries were significant centers of Byzantine science, and the teachings at the University of Constantinople were mostly delivered by men of religion.
While Stephanus of Alexandria was not officially an ecclesiastic, several references highlight the importance of his Christian fervor in his works. King Heraclius is said to have invited Stephanus of Alexandria shortly after his ascent to power around 610, where Stephanus would have taught philosophy and alchemy for several years.
The role of Emperor Heraclius in the development of a genuine alchemical domain among Byzantine thinkers is vaguely defined, but some claim that the pursuit of the philosopher’s stone had become an obsession for him. The ability to transform metals into precious metals held great allure for the rulers and societies of the time, even though alchemists, like Stephanus of Alexandria, appeared to dissociate themselves from the material aspect of this practice.
A student of Stephanus of Alexandria, named Marianos or Morienus, is said to have introduced alchemy to the Muslim world by initiating the Umayyad Prince Khalid ibn Yazid around 675. Muslim princes were quickly drawn to the promises of this occult science and showed a keen interest in it in the following centuries.
Michael Psellos
Michael Psellos (left) with his student, Byzantine Emperor Michael VII Doukas.
After the death of Emperor Heraclius, the intellectual circles of Constantinople found their work contested by the Church. Consequently, Byzantine studies and writings experienced a significant decline in the centuries following the 600s.
Scientific practice was banned from the Byzantine territory for several centuries before being reinstated during the reign of Emperor Constantine VII, known as the Porphyrogennetos or Purple Born (944–959). One of the central figures in Byzantine scholarship, and the one who would bring scientific practice to the forefront, is the scientist Michael Psellos (1018–1078).
Michael Psellos is one of the most influential figures in Byzantine scientific history, credited with restoring the reputation of scientific institutions such as the University of Constantinople, which had seen a sharp decline since the end of Emperor Heraclius’ reign. At the age of 25, Psellos claimed to possess all the knowledge of the world. He quickly established himself as an exceptional speaker and became a renowned and respected professor, leading to an invitation by Emperor Constantine IX Monomachos to pursue a career in the imperial chancellery. Psellos played a crucial role in the administration of the empire.
During his reign, Emperor Constantine Monomachos advocated for the restoration of the importance of culture in Byzantine society, providing a platform for intellectuals like Psellos and their teachings. It appears that Psellos took this opportunity to legitimize the alchemical domain, notably with his writings “Epistle on Chrysopoeia” and a letter addressed to Patriarch Michael I Cerularius (Patriarch of Constantinople) titled “How to Make Gold.”
This letter posits that the transmutation of metals is a completely natural process and presents a series of recipes for transforming various metals into gold. However, according to the Belgian historian Joseph Bidez, who published Psellos’ writings in 1928, Psellos possessed inaccurate knowledge of alchemical processes. Despite this, Michael Psellos had an impact on the evolution of Byzantine culture and the restoration of alchemy as a subject of study on par with philosophy and rhetoric.
The Transmission of Alchemical Concepts to the West
Later on, alchemy became primarily the concern of the Arabs and then of great European alchemists like Nicolas Flamel, but Byzantine alchemy continued to influence its practice, notably through the writings of the Catalan scientist Arnoldus de Villa Nova, whose works are believed to have emerged in Southern Italy in the 14th century.
His translations of alchemical works from the Byzantine Empire are thought to have influenced the practices of humanist thinkers during the Renaissance. The fall of Constantinople in 1492 is also said to have led to an exodus of thinkers and priests who possessed manuscripts containing alchemical processes still unknown to the West.
The Christmas tradition in Germany encompasses traditional elements of the Christmas celebration. Like all traditions, Christmas customs in Germany vary regionally and are constantly evolving. The starting point is the celebration of the birth of Jesus Christ. In tradition, some older pre-Christian winter and light customs have been added and merged with Christian motifs. In other Central European countries, Christmas is celebrated similarly. The festive day is December 25th. The celebrations begin on the Holy Evening (also Holy Eve, Holy Night, Christ Night, and Christmas Eve), on December 24th. Depending on the denomination, the Christmas season ends on January 6th, the Feast of the Epiphany, or on the following Sunday, the Feast of the Baptism of the Lord. Today, Christmas symbols, songs, and decorations have already shaped the cityscape in many places since the end of November.
Christmas customs were Christianized in nativity plays as special spiritual performances and have been depicted in Christmas cribs since the 16th century. The scenic representations can be traced back to the 11th century in France. The contemporary Christmas celebration in the German-speaking region with a family gathering featuring a Christmas tree, Christmas carols, nativity scenes, gifts, and attending a church service is a cultural manifestation of the middle-class family of the 19th century (Biedermeier).
Christmas market, Frankfurt am Main, Germany.
In folkloric and Germanic research, until the first half of the 20th century, including by the Brothers Grimm, it was presumed to be a very ancient tradition, and attempts were made to construct continuity back to Germanic antiquity. Thus, the world tree of Germanic mythology or the midwinter tree, was seen as a direct precursor to the Christmas tree. This also aligned with the ideology of National Socialism, which sought to blend the Christmas festival with Germanic and Scandinavian Yule traditions to establish it as the “Festival of the National Community under the Christmas Tree” (see Nazi Christmas cult).
Christmas Customs in Germany
Customarily, in Central Europe, the specific manifestation of Christmas and Advent traditions primarily arose in a region characterized by a cold and dark winter climate. In the Southern Hemisphere, Christmas coincides with summer, leading to different customs. The evergreen Christmas tree lacks a corresponding symbolic significance there.
Preparation
The Christmas celebration on December 25 is preceded by a four-week Advent period. Originally a fasting period, the Old Church placed it between November 11 and the Feast of the Epiphany on January 6. The present form of Advent dates back to the 7th century. Initially, there were between four and six Sundays in Advent, until Pope Gregory eventually fixed the number at four in accordance with the Roman Rite. However, in the Ambrosian Rite, the Advent period still lasts six weeks. Since 1917, Advent fasting is no longer mandatory under Catholic canon law. Numerous traditions accompany the Advent season, including the Advent calendar, indicating the remaining days until Christmas, hanging a Saint Nicholas boot on the doorstep on the evening before Saint Nicholas Day, and the Christmas market, prevalent in many cities.
Christmas Tree
Christmas tree on the Potsdamer Platz (Sony Center) in Berlin, Germany.
In Central Europe, the Christmas tree (referred to as Christbaum in some German regions) is placed in churches, homes, and on large squares in towns, adorned with strings of lights, candles, glass balls, tinsel, angels, or other figures. The domestic Christmas tree often remains in the room long after Christmas, sometimes until the end of the liturgical Christmas season. Two candle-adorned Christmas trees have stood annually since 1621 at the Augustinians in Neustift, flanking the nativity scene.
The origin of the Christmas tree is likely the Tree of Life (Bible) from the widespread medieval mystery plays on December 24. From around 1800, the adorned Christmas tree could be found in the upscale residences of Zurich, Munich, Vienna, and Transylvania. Initially considered Protestant, it gradually gained acceptance among Catholics as well. Princess Henrietta of Nassau-Weilburg introduced it in Vienna in 1816. The Franco-Prussian War popularized the Christmas tree in France, and in 1912, the first “public” tree stood in New York.
The adorned Christmas tree is now a central element of the family Christmas celebration. Until the 18th century, it could only be found in royal courts and later among the bourgeois upper class. It gained popularity among the lower bourgeoisie, not least because the Prussian king, during the Franco-Prussian War against France, had Christmas trees set up in the trenches and field hospitals. Afterward, the Christmas tree continued to spread and assumed the central role in the ceremony of the domestic family celebration that is now considered self-evident (children standing in front of the closed door, candles on the tree being lit, the door opening, collective singing, joint opening of gifts, shared meal).
The collective attendance of Christmas Eve services such as Christvesper (“Christmas Vespers”), Christmette (“Midnight Mass”), or Christnacht (“Christmas Eve”) is not only a fixed component of Christmas for regular churchgoers among Christians. These services are usually well-attended in German-speaking regions. Services, often beginning on Christmas Eve with children’s services, take place on all Christmas days. The reading of the Christmas story from the Gospel of Luke and singing Christmas carols are part of the liturgy. Also, attending a performance of a Christmas oratorio is widespread in the time before and after Christmas, especially in the Lutheran Protestant tradition.
Nativity Scene
The most original Christmas custom is the tradition of the nativity play, which vividly recreates the Christmas story. Families gather around the nativity scene on Christmas Eve, commemorating the birth of Christ. The history of the nativity scene, now an integral part of Christmas, likely began in the 13th century, with the use of the nativity scene in worship possibly dating back to the 11th century. In the castle chapel of Hocheppan near Bozen, around the year 1200, the birth of Jesus was first depicted in the German-speaking region. This representation culminated in the Christmas celebration before the nativity scene and Christmas tree.
Martin Luther shifted the customary gift-giving, which was previously observed in his household on St. Nicholas Day (there are household records from the Luther residence documenting gifts for servants and children on St. Nicholas Day in the years 1535 and 1536), to Christmas Eve. This change occurred because the Protestant Church did not engage in saint veneration. The new Protestant gift-bearer was no longer St. Nicholas but the “Holy Christ,” as Luther referred to the infant Jesus. From this abstraction, the angelic Christ Child emerged in Thuringia and other regions, appearing in Christmas processions since the 17th century, where Mary, Joseph, and the Jesus Child paraded through the streets—akin to today’s Star Singers—accompanied by white-clad girls with open hair as angels, led by the veiled “Christ Child.” After 1800, Knecht Ruprecht, originally the punishing companion of St. Nicholas and the Christ Child, gradually transformed into Santa Claus.
Santa Claus
According to the German Atlas of Folklore in 1930, Santa Claus (predominantly in the Protestant North and Northeast) and the Christ Child (mainly in the West, South, and Silesia) were the gift-bringers. The demarcation ran between Westphalia and Friesland, Hesse and Lower Saxony, Thuringia and Bavaria, going through southern Thuringia, southern Saxony, and Silesia. In the 18th century, it was different: St. Nicholas delivered gifts in Catholic areas, while the Christ Child did so in Protestant regions. With the increasing popularity of Christmas and the Christ Child, the gift-giving date in Catholic regions shifted from St. Nicholas Day to Christmas Eve, adopting the Christ Child tradition.
Santa Claus – Dresden, Germany.
Santa Claus is a syncretic figure, blending elements from St. Nicholas, Knecht Ruprecht, and the rough Percht in a demystified form. A drawing by Moritz von Schwind in the Munich Picture Sheet No. 5 from 1848, titled “Herr Winter” – though avoided by people – is considered an early representation, although not the only one. Older descriptions in poetic form come from North America, where he is called Santa Claus. The attire, predominantly depicted as red in Germany after 1945, was adopted from Knecht Ruprecht, and the flowing beard from common depictions of God the Father. In traditions for young children, he brings gifts, but to naughty children, he brings a switch.
Secret Santa and Gift Exchange
The Nordic legendary figure of Nisse (Danish Niels for Nicholas), adapted in German as Wichtel, with its red hat, bears resemblance to Santa Claus. Derived from this is the custom of Secret Santa during the pre-Christmas period, where individuals exchange gifts anonymously in a random pairing of giver and receiver.
Gifts known since ancient times for New Year’s persisted well into the 20th century, locally even until today, as monetary gratuities for mail carriers, newspaper carriers, garbage collectors, etc. According to Börsenblatt, in 2007, one-fifth of intra-family Christmas gifts were passed on in the form of vouchers or cash. However, the tradition of Christmas gift-giving traces back to St. Nicholas gift-giving. “Lüttenweihnachten” refers to decorating a Christmas tree for animals in the forest with feed.
Christmas Singing
In the intimate setting of homes, much singing and musical activity takes place on Christmas Eve and the first and second holidays. In a time of diminishing familiarity with folk songs and hymns, German Christmas carols remain a part of the residual traditional German song repertoire for many people in the German-speaking region, allowing them to join in the singing. In the public sphere, the collective singing of Christmas carols by large groups of people has evolved into a distinct tradition, particularly in Berlin.
Christmas Meals
Stollen.
Christmas usually involves an elaborate Christmas feast on the first holiday, featuring specific dishes such as Christmas goose or carp, as well as specially crafted Christmas treats like Stollen or regional gingerbread specialties such as Aachener Printen, Nuremberg gingerbread, or Liegnitzer Bombe.
In some regions, on Christmas Eve, likely for the simplicity of preparation, traditional dishes like stew or sausages with potato salad are served. In the north, the potato salad is prepared with mayonnaise, while in the south, only vinegar, oil, and broth are used. A straightforward dish is associated with the Lower Silesian Christmas, the “Breslauer Mehlkloß” (made from flour, milk, butter, and egg).
In Altbayern (Old Bavaria), the animal fattened for the Christmas feast, usually a pig or occasionally a Christmas goose, is colloquially referred to as the “Weihnachter.”
In the Vogtland and the Erzgebirge, the so-called Neunerlei, a Christmas menu with nine courses served on Christmas Eve, is prepared. It typically includes sausages, dumplings, sauerkraut, goose or pork roast, nuts, and mushrooms. In many families, coins are placed under the plates.
Other Christmas Customs in Germany
Among the less reflective Christmas traditions is the telling of traditional spooky stories (sometimes ironic, like snowmen by the campfire, or not, like The Man with the Head Under His Arm), especially while awaiting the gift-giving in the anteroom on Christmas Eve. This seems to be particularly prevalent in North and Northeast Germany. In Alpine traditions in December and January, perchta, figures associated with driving away winter, play a role.
Another custom on Christmas Eve is the “Christklotz” also known as Yule Log. In Berchtesgadener Land (a Bavaria district), the Christmas shooting of the Christmas marksmen marks the last week before Christmas. They shoot every day at 3 o’clock in the afternoon from their positions—additionally on Christmas Eve before the Christmas Mass.
A supposedly old German custom imported from the USA revolves around a Christmas tree decoration in the shape of a pickled cucumber, known as the “Christmas Pickle.” The “Christmas Pickle” is discreetly attached to the Christmas tree before the gift-giving ceremony. The recipients, usually children or teenagers, search the tree for the hidden ornament before opening their presents. The person who finds the “pickle” first receives a special, additional gift. Since 2009, this Christmas tree ornament, resembling spice pickles, has been available at German Christmas markets. Glassblowers offer three different sizes to tailor the difficulty level to the age of the children.
As darkness falls during the Advent season, numerous windows in homes are illuminated by Schwibbögen. This tradition originated in the 18th century in the Ore Mountains mining regions and is increasingly spreading to neighboring countries. Every year, the Deutsche Post issues special stamps for Christmas. In many places, Christmas markets, also known as Christkindlesmarkt or Glühweinmarkt, have become established during the pre-Christmas period. They are characterized by stalls selling Christmas items and gifts, mulled wine stands, and an increasing number of food stations.
Abstention from Christmas Celebrations in Germany
The reformist churches believed that Christmas festivities originated from pagan customs and were associated with the Catholic Church, so they fundamentally rejected them. In 1550, in Geneva, all non-biblical celebrations were banned, leading to severe conflicts. John Calvin was less strict on this matter. In 1560, John Knox prohibited all church festivals, including Christmas, in Scotland.
Scottish Presbyterians adhered to this ban into the 20th century. Quakers and Puritans of the 17th century also rejected Christmas as a holiday and continued with their usual activities. In that period, the English Christmas celebration included not only church services but also feasting, revelry, dancing, and gambling. In 1647, Parliament enacted a ban on such festivities, leading to street riots between supporters and opponents of Christmas. After 1660, the ban on celebrations was no longer enforced.
Only in recent times have regulations adapted to the behavioral patterns of their cultural surroundings. In the 19th century, Christmas saw a significant resurgence in England, possibly influenced by Prince Albert from Germany, whom Queen Victoria had married. The development in the USA followed a similar trajectory. In regions where predominantly Presbyterians, Mennonites, Quakers, and Puritans lived (New England, Pennsylvania), there was no Christmas celebration until the 19th century. In the southern regions, English settlers retained their Anglican customs from the 17th century. Dutch settlers brought their Sinterklaas (St. Nicholas) to New York, later evolving into Santa Claus.
In some Jewish households living as a minority in a Christian environment, there is a phenomenon called “Chrismukkah,” where, for example, Christmas trees are set up in living rooms and adorned with balls engraved with the Star of David during the Hanukkah festival.
Islam
In some Muslim households, a goose may be placed on the table for Christmas, and children receive gifts. As the birth of Jesus Christ is extensively described in the Quran, Muslims are not unfamiliar with the origin of the Christmas festival.
Shift of Christmas Customs to the Advent Season
A noticeable change in customs has been observed in the Advent season since the 20th century. Originally observed as a period of fasting, contemporary practices of the Christmas festival are already being embraced in the Advent season. One significant aspect of this is the prevalence of Christmas markets in most German-speaking city centers, some of which have traditions dating back to the Middle Ages.
Christmas in German: “Weihnachten”
In its original form, Christmas is called “Weihnachten” in German which means “the holy nights” in old Germanic. The customary celebration lasted for twelve days, which is why the phrase is plural. Now it’s running in Germany from the evening of December 24th through the 26th.
In December 1952, the capital of the United Kingdom, London, experienced an unprecedented air pollution event known as the “Great Smog of London.” Lasting for five days, this smog severely impacted London’s transportation, daily life, and health, leading to thousands of deaths. It stands as one of the most severe air pollution events of the 20th century, serving as a pivotal moment in triggering environmental awareness and legal reforms.
Background and Causes of the Great Smog
The backdrop of the Great Smog of London was the industrialization and urbanization process in the United Kingdom. Since the late 19th century’s industrial revolution, London became a thriving center of industry and commerce, with a continuous increase in population and buildings. Coal, serving as the primary energy and fuel source, was extensively used for power generation, transportation, manufacturing, and heating.
The immediate cause of the London smog was the unusual weather conditions in November and early December of 1952. London experienced rare cold and windless weather, with temperatures below freezing, high humidity, and overcast skies. This weather led to an atmospheric phenomenon known as “temperature inversion,” where the air temperature at higher altitudes was higher than that at lower altitudes, preventing vertical convection and creating an “inversion cap” that trapped London’s air and pollutants near the ground.
In this situation, London residents, in their pursuit of warmth, burned a significant amount of low-quality coal containing high levels of sulfur and ash. This coal combustion produced more particulate matter and sulfur dioxide. These pollutants were unable to disperse and instead reacted with water vapor and other chemicals in the air, forming toxic substances like sulfuric acid, hydrogen chloride, and fluorides. These substances adhered to the particulate matter and condensed into droplets, creating dense smog.
—>The atmospheric pollutants, such as sulfur dioxide and sulfur dioxide, emitted from sunlight, thermal power plants, diesel vehicles, etc., lingered in the cold air, concentrating and forming a highly acidic sulfuric acid fog with a pH of 2. The maximum concentration of sulfur dioxide was around 0.1 ppm during normal times, reaching 0.7 ppm during the smog event, and the concentration of suspended particulate matter exceeded 1.7 mg/m3 from the usual 0.2 mg/m3. Source
Impacts and Consequences of the Great Smog
Nelson’s Column during the Great Smog. Image: N T Stobbs.
The effects of the Great Smog of London were devastating. Starting on December 5th, London was covered in a thick yellowish smog, reducing visibility to just a few meters or even centimeters, accompanied by the smell of rotten eggs, making breathing difficult both outdoors and indoors.
The smog posed significant challenges to London’s transportation and daily life. Public transport, including the subway, buses, taxis, and trains, suffered severe disruptions, with many routes forced to shut down or experience delays. People had to resort to walking or cycling, but even these activities were difficult because of poor visibility.
A chart produced by E.T. Wilkins c.1953 showing an apparent excess of 12,000 deaths in London for the winter 1952-1953.
The health consequences of the smog were severe. The toxic substances in the smog irritated people’s eyes, throat, nose, and lungs, causing respiratory diseases such as bronchitis, pneumonia, asthma, and emphysema. Statistics indicate that during the smog event, London’s mortality rate doubled compared to normal times, with an estimated 4,000 deaths occurring that month and subsequent death toll estimates potentially reaching as high as 12,000. Source
Reflection and Reforms Following the Great Smog
Map prepared by the Fuel Research Station showing where pollution was concentrated across the city during the smog of December 1952. Catalog ref: MH 55/2661
The Great Smog of London prompted heightened awareness and reflection on air pollution and environmental protection. People recognized the costs of industrialization and urbanization, as well as the drawbacks of coal as an energy and fuel source. Efforts were initiated to seek cleaner, more sustainable development methods and more effective air quality monitoring and management systems.
—>When the fog lifted, an assessment was conducted, revealing that during the days of extreme smog, the death toll in London had nearly tripled. The death rates for individuals aged between 55 and 65 increased by 142 percent, while those in the 65 to 75 age group rose by 235 percent. The maximum SO2 concentration reached 3.82 milligrams per cubic meter of air.
The smog event led the UK government and parliament to enact a series of laws and measures aimed at reducing air pollution and preventing similar events. Most notably, the Clean Air Act of 1956 was passed, marking the UK’s first law specifically addressing air pollution and one of the earliest environmental laws globally. The act established standards and limitations for coal burning, encouraged the use of smokeless coal or alternative energy sources, created smoke control areas, imposed fines on violators, provided subsidies to affected residents, regulated emissions from factories and power plants, and implemented air quality monitoring and reporting.
—>One significant action was the drastic reduction in the number of open fireplaces. However, the implementation was slow, leading to another, less hazardous smog in 1962. Subsequently, additional measures were adopted from 1968 onwards (Clean Air Act 1993).
Internationally, the Great Smog of London drew attention and responses from the global community, fostering the environmental protection movement and cooperation worldwide. Many countries and regions also formulated similar laws and policies to control and reduce air pollution, improve air quality, and safeguard human health and life.
Researchers Clarify the Cause of the London Killer Fog
A police officer attempts to guide traffic amid heavy smog in London, 1952 Image: Telegraph.
—>There were work stoppages, revenue losses in public transportation and among taxi drivers. Additional costs incurred due to the necessary street lighting during the day and the deployment of 18,000 extra police officers sent to London, as there was a significant increase in thefts and robberies.
Now, researchers claim to have discovered what made the weather so deadly: the combination of specific weather conditions with exhaust particles that turned into poison. Diminishing winds were the beginning. During days of calm winds in early December, chimneys from power plants and factories blew warm air upward, while winter air cooled the ground.
Soon, a fatal layer of mild air formed, sitting above the cold air like foam on beer. The two air layers mixed little, creating inversion weather. At ground level, pollutants accumulated, hanging over the city like a dirty bell. Less and less sunlight reached the ground, which continued to cool until the cold air couldn’t hold moisture anymore. The moisture gathered on particles, condensing into fog.
The air at ground level continued to cool, prompting Londoners to heat up more. Sulfur emissions from coal combustion filled the haze from chimneys and factory stacks; this was already known. However, researchers wanted to understand why sulfur dioxide turned into toxic acid. Their concern was that the deadly fog could recur in smog-plagued Asian cities.
The crucial ingredient, they found, was nitrogen dioxide, as reported by scientists led by Gehui Wang of the Chinese Academy of Sciences in the Proceedings of the National Academy of Sciences. The substance also forms during coal combustion and causes sulfur dioxide to turn into sulfuric acid when combined with water.
In the London fog, another coincidence triggered the chemical process, the scholars wrote: the air was exceptionally humid due to rare weather conditions, allowing a lot of acid to form. When the water droplets later evaporated, they left behind acid in a toxic concentration that people eventually inhaled.
In China, however—that’s the good news—the smog air is not acidic, the study’s authors note. Apparently, at least one ingredient of the complex London toxic recipe is missing.
A crucial difference is likely that the fine particles on which the fog in Asian metropolises settles are smaller; consequently, less acid forms in the tiny water droplets.
But even in China, large amounts of the fatal ingredient nitrogen dioxide enter the air; hence, the researchers warn: The right interplay of all factors can create deadly fog elsewhere, not just in London.