A Benedictine abbey, the Church of San Pietro was founded in the 10th century. The main court is dominated by the polygonal clock-tower, allegedly built on the site of an Etruscan tomb that was used for its construction in the 13th century. After a partial collapse, the upper section was rebuilt in 1463. Rich in art, there are frescoes dating from the 14th century as well as paintings by Perugino. The interior is a mixture of ancient columns and has a Palaeochristian basilical structure. The Gothic wooden choir is considered to be one of the finest in Italy and was completed between 1525 and 1591.