After some initial difficulties the monastery and the settlement round it, at that time known as Offoniscella ("cell of Offo"), gradually flourished.
In the 8th century Saint Pirmin introduced the Rule of St. Benedict and revived the fortunes of the abbey, as demonstrated by the rush of new postulants from the nobility at this period.
In 1016 the Emperor Henry II stopped at the abbey while returning to Frankfurt and visited the tomb of the founder Offo.
The grave was covered by a precious mosaic showing Cain murdering Abel, which survives and can be claimed to be the oldest of its kind in Germany.
The remains of various predecessor buildings were preserved in a part of the church basement after the excavations were concluded and are open to the public.