The Cathedral, dedicated to the Assumption, stands on Via Arco di Augusto. It was rebuilt in 1140 after a fire had destroyed the earlier building. Its brick and sandstone façade is typically Romanesque, with a richly decorated ribbed portal, where at the centre you can see a Gothic portal which was clearly influenced by Cosmatesque inlaid marble decorations that brighten the pillars and the ribs of the portal and that alternate the smooth little columns in white and pink marble. They strongly contrast with the strongly emphasized images of the divine lamb carved at the centre of the lintel.

The church bell tower to the left was built to replace the original cylindrical bell tower which was destroyed during the Second World War. In the interior, divided into a nave, two aisles and side chapels which were added from the 14^th century onwards, there are several noteworthy features. These include a pulpit made from sculptures from the earlier Church, with Romanesque reliefs representing episodes from Christ's childhood, and the seventeenth century Nolfi Chapel on which the architect Girolamo Rainaldi collaborated. This was frescoed with "The Story of the Virgin" by Domenico Zampieri (Domenichino) between 1618 and 1619. In the Chapel of the Patron Saints you can see paintings of "The Virgin with Saints Urses and Eusebius" by Ludovico Carracci while on the main altar is "The Virgin in Glory" by Sebastiano Ceccarini.