The Cathedral of Santa Maria Assunta was built in the Romanesque style in the eleventh century. During the thirteenth century there were the first upheavals, with the erection of the facade and bell tower. The facade was remodeled several times, until it assumed the present "hut" conformation; it was added in the fifteenth century, by Antonio Barocci, the Renaissance-style porch, covered by lush, ornate entablature and a terrace. The top, in Romanesque style, is divided into two overlapping bands with three large niches lancet and three rosettes; in the central niche, there is a mosaic depicting "Christ Enthroned between the Virgin and St. John the Evangelist" (1207). On the left, it stands the thirteenth-century bell tower, with a square plant, with a mullioned window and an octagonal spire. Between the seventeenth and eighteenth centuries, the interior underwent extensive renovations in Baroque style was completely rebuilt the nave and the two side. The plant is a Latin cross, with three aisles of six bays each transept, semicircular apse and dome coverage of the cruise. The aisles and the fifteenth-century apse are decorated with frescoes by Filippo Lippi (1467-1469) depicting stories of the Virgin. At the center of the presbytery is the main altar in polychrome marble, work by Giuseppe Valadier. Attached to the Cathedral is the Bishop's Chapel Eroli frescoes by Pinturicchio (1497).