Castle of bishop-counts. It was erected in the late 12th century by Gerardo de Taccoli. The tower houses a bell that since 1403 has called the Main Council. A twin tower was demolished in 1516. After alterations in the 1800′s it was completely rebuilt after the damage suffered in an earthquake in 1873 by the engineer Giorgio Pagani Cesa. In front is the fountain of S. Gioatà (1410).