San Pietro monastery dates back to the tenth century, as an episcopal foundation and it gained independence in 1148. After a period of crisis, in 1434 it was aggregated with the Congregation of St. Justine, then Cassinese. It was made famous by monks who shone in their studies (B. Bacchini) or who had high-level roles, two of whom became Cardinals. Suppressed during the French Revolution (1796), it was reopened by the Duke of Modena, then closed again by the House of Savoy (1866). In both cases one monk stayed on as parish priest. Apart from a brief period (1926-1938) Benedictine monks have always lived in this abbey.

The current abbey church dates back to the end of the fifteenth century and was consecrated in 1518. The splendid Renaissance cloister is from the same period. The façade of the church was the work of P. Barabani, with terracotta decorations by the Bisogni brothers and an equally interesting bell gable. Inside are various terracotta decorations by A. Begarelli and paintings by F. Bianchi Ferrari, E. dell'Abate, J. Cavedone, G. delle Catene, J. van Ghelde, G.B. Ingoni, L. Lana, P. Munari, G. Romanino, C. Ricci, E. Setti, G. Taraschi, F. da Verona and others. The fine wooden chancel is by G. F. Testi. In addition to the beautiful fronts in scagliola on all the altars, there is also a majestic sixteenth-century organ by G.B. Facchetti. The sacristy is decorated with frescoes by G. da Vignola, and fine wooden inlay furnishings by G. Brennona.

It would seem that, from the tenth century on, the Benedictine monastery had a dispensary, at least for the internal infirmary, but it wasn't until the abbey complex was rebuilt in the sixteenth century that the dispensary was moved to its position close to the main entrance. From this period and above all in the following centuries, and therefore until the health reform in the second half of the eighteenth century, the Benedictine dispensary was, for its importance, the focal point of the medical-pharmaceutical services of the city and the entire dukedom. 

The products on offer included various famous preparations made from spices and flowers grown in the adjacent courtyard. They also prepared “pastes for perfumes” using incense and juniper, myrrh and carnation, and above all “Theriac”, for which the monastery had the ducal exclusive for both production and sales. “Theriac”, was made from the macerated flesh of a female viper from the Euganean Hills, not pregnant and captured a few weeks after winter hibernation. The head and guts were removed, the rest was boiled in salted water, flavoured, ground and kneaded with dry bread, then mixed with opium and finally formed into walnut-sized balls and put to dry. It was considered a remedy for a long list of illnesses.

Closed in 1796, the Dispensary was reopened in 2007 and it sells products from other Italian and European Benedictine monasteries.