The Duomo was built between 1437 and 1487, on the site where a 10C basilica once stood; its façade remains incomplete. Its east side gives onto Piazza Danti, but it is its left-hand side, turned towards Piazza IV Novembre, that draws the most admiring glances. Inside, take in the interesting Descent from the Cross by Barocci (1567), which inspired Rubens, and, in the left-hand chapel, a ring said to be the wedding ring of the Madonna.