The Collegiate Church is located in Piazza delle Piane next to the Palazzo Negroni. It was built in the 13th century as a church with three naves and dedicated to Saint Maria Assunta. The Collegiate Church of Santa Maria Maggiore was rebuilt between the 17th and 18th centuries. During recent restorations, original parts of the beautiful brick facade have come to light. There are nice pictures to see, a recently restored wooden group and the organ.