The physical structure of the convent can be compared to giant building blocks, composed of parts from over twelve centuries. The oldest monastery and church with its precious Carolingian cycle of paintings was created from 775 AD onwards. It can be assumed that Charlemagne himself actively supported the building of St. Johann. Since then the compound has been remodelled significantly at least eight times. Buildings were torn down and new ones erected. Each era left its traces with paintings, plaster work, vaults, paneled rooms, but also with artifacts of the monastery's mundane and religious life.