Arriving from Borgo San Pietro, the Benedictine abbey (after which this neighbourhood is named) is introduced by an imposing Romanesque bell tower. The church overlooking the square was built by Benedictine monks during the 10th century, according to documents; it was restored several times until the final renovation during the 18th century.
The façade is rectangular and divided by a cornice; it has three doorways with the central one flanked by two lions. Its upper band has three rose windows. The façade ended with a tympanum unfortunately demolished after an earthquake in 1832.
The church interior, restored in 1954, has three naves; the central one is covered by a wooden ceiling, the aisles by barrel vaults. The presbytery is raised up 5 steps and is above the crypt. The dome is extremely unusual; it is composed of 31 rows of jutting out bricks, perhaps influenced by the Provencal style.
Frescos were uncovered in 1954 when the Baroque altars were demolished. On the counter façade are two 14th century tombs.
An Early Medieval sarcophagus under the high altar holds the body of San Vittorino, a martyr, the third bishop of Assisi and the co-protector of the city. The splendid Gothic chapel of the Blessed Sacrament contains a precious triptych; the chapel on the left is decorated with frescos portraying Saints and hunting scenes dating back to 12th century, influenced by Emperor Frederick II culture.