Located in a rather secluded area near the lake, at the centre of its vast territory in which many of its auxiliary churches are situated, the church was built in the 7th/8th century on top of a pagan temple and an older building from the 5th/6th century. Beside it are ancient remains, possibly from a Roman villa. Rebuilt in the 9th century, the church has three aisles divided by three rectangular pillars supporting round-headed arches. The parish church is the most important medieval monument in the area also in view of the decorations and artwork inside. Stupendous frescoes include the 12th century The Martyrdom of Sant'Ursula and Companis , which is considered an extremely rare example of Romanesque art, the 14th century Annunciation, and the Madonna Enthroned between Saints Sivino and Rocco.