Cathedral was built by Duke Mansone I from the year 987. The current facade was built in the nineteenth century by Errico Alvino and presents a Neo-Moorish style, with neo-Gothic influences, preceded by Cloister of Paradise and Church of Crucifix. The bell tower was built between 1108 and 1276. The main portal has a lunette, which contains a fresco by Domenico Morelli and Paolo Vetri, and a bronze door, fused to Constantinople. The interior, remodeled in Baroque forms, has a basilica plan with a transept and an apse; the whole is covered with marbles that contain ancient columns. The aisles are covered by a coffered ceiling. On the high altar there is a large canvas depicting Crucifixion of St. Andrew the Apostle, copy by Mattia Preti. The chapels contain works of Gothic and Renaissance art. Crypt, built on the tomb of the patron saint, is adorned with valuable frescoes, the largest of which represents the arrival of the body of Sant'Andrea in Cathedral. On the altar there are the bronze statue of Sant'Andrea, by Michelangelo Naccherino, the marble statue of San Lorenzo, by Pietro Bernini, and that of S. Stefano, by a local sculptor.