Both the monastery and the church of S. Pietro date back to the X century, located in a land originally considered outside the city walls. Founded by the Benedictines of Mount Subasio, its construction took place in a period of “strategic” expansion of the Order. At the beginning of 1200 the abbey was rebuilt again, hence, it assumed the current Romanesque-Gothic shapes, which are particularly fine and harmonious.

The rectangular façade, realized with the characteristic pink stone of Mount Subasio, is stressed by three portals as many rosettes, and it is divided by a frame with overhanging arches; the central portal is flanked by two lions. Originally, the façade ended with a tympanum, which was destroyed by an earthquake in the XIX Century.

The Abbey was consecrated by Pope Innocenzo IV in 1253. The interior was restored in 1954: it is stressed by three naves separated by pillars, a raised presbytery, a semi-circular apse and a dome; the counter-façade and the sides of the presbytery preserve funerary monuments of some nobles of Assisi from the XIII and XIV Centuries, while the walls and the chapels are decorated by paintings (dating back to the same period). Particularly worth noticing is the Chapel of the Most Holy Sacrament with its Gothic style, accompanied by a precious triptych by Matteo da Gualdo.

Although this may apparently seem an irrelevant fact, the main characteristic of the Abbey is that of not belonging to the Franciscan Order, but to the Benedictine Order instead. This gives to the building an interesting characteristic: that of being part of a greater identity in the panorama of places of worship of Assisi. In fact, a particular edict issued at the end of 1200, prohibited the city of Assisi to build or leave its lands to religious orders different from the Franciscan one.