Together with the Basilica di San Pietro, the church of Santa Maria Maggiore is an excellent example of Romanesque architecture in Italy. It is also the first cathedral in Tuscania and the only one, because of an ancient privilege, to have an underwater baptismal font that is still well preserved today. Its construction dates back to the 8th century, but the church was almost entirely rebuilt between the end of the 11th and the beginning of the 12th century and took on its present form with three naves. Alongside it, is a massive bell tower that served a dual function: that of inviting the faithful and that of serving as a lookout and defence point, considering its strategic location at the meeting point of many busy roads in the period. The façade of the church resembles that of San Pietro with a splendid rose window and a loggia below, but there is no tympanum to top it off. The three portals with their lunettes are much more elaborate than those of the larger one. The local volcanic stone tuff, is the predominant building element. The main portal, the central one, is made of white marble, with four columns on each side, with Corinthian capitals on which rest the small arches that serve as the crowning for the lunette, which features a high relief of the Madonna and Child Enthroned, the Lamb of God, the Sacrifice of Isaac and the Flight into Egypt. Portraits of San Pietro and San Paolo are also carved on the sides of the entrance portal. The portals on the right and left are also well crafted, with plant motifs, symbolic figures, columns and Corinthian capitals. On the inside, with a nave and two side aisles, there are columns and pillars still preserving some Romanesque frescoes and sculpted capitals decorated with monstrous subjects. Each of the naves corresponds to an apse, with the central one being larger and ending with a superb triumphal arch. Above the arch, a 14th-century fresco by Gregorio and Donato of Arezzo representing the Last Judgement is still visible, although it has been subjected to several restorations. Particularly noteworthy is the octagonal immersion baptism font in the right aisle, which dates back to the 13th century.