The architectural changes to the buildings makes it difficult to trace the true story because the changes were made by reusing old materials. Probably the first group of buildings are Byzantine of the fourth century, built on an existing Roman building. The monastery was functioning in the eighth and ninth centuries, during the flowering of monasticism in Italy and of the Benedictine order, when Sabina was donated by Charlemagne to Pope Hadrian I. The church and the crypt are Romanesque. The "in Argentella" denomination is due to the presence of a spring in the valley, which was probably nearby. A source of water still flows into the underground crypt. This water was considered therapeutic and miraculous and, according to tradition, the people bathed there on June 24, the feast day of San Giovanni (St John).