Did Charlemagne Really Invent the School?

The school's origins may be traced back to the Carolingian Emperor. Yet, what exactly was Charlemagne's impact on learning?

Basilica-cathedral of Notre-Dame de l'Annonciation in Moulins. Detail:Charlemagne.
Basilica-cathedral of Notre-Dame de l'Annonciation in Moulins; stained glass window of Saint Catherine, known as the dukes' window, end of the 15th century. Detail:Charlemagne.