This church, dedicated to St Julian from the 1200's onwards, is at the centre of the old quarter that grew from early Roman times along the start of the Via Aemilia. The vicinity of this road also influenced the building of the Benedictine monastery, dating back at least to the 9th century and originally dedicated to Saints Peter and Paul.

The monastery and church, one of the city's most important in the Middle Ages, were altered several times. In the mid-1500's the mediaeval church, with a central nave and two side aisles and crypt, was rebuilt in its present form. The monastery was also altered in the same period, and excavations have revealed remains of the portico and the paving of the cloister, still to be seen in the adjacent Tiberius Cinema, together with several tombs from the graveyard that occupied the site in Byzantine times. At the centre of the courtyard stood a monumental well in Istrian limestone by a 16th-century Venetian sculptor. The architrave of the well, with the sculpted figures of Saints Peter and Julian, is now on display at the Civic Museum.

Apart from paintings by the Venetian School, the church has a polyptych by Bittino di Faenza with scenes from the life of St Julian, in the third chapel on the left, and an altarpiece by Paolo Veronese, showing the martyrdom of the saint, conceived almost as a theatrical scene of strong emotive impact. Set above the main altar within a surround of Palladian inspiration, the large painting dominates the marble sarcophagus said to have been carried here from Dalmatia with the relics of the saint.