The Church of San Paolo is already mentioned in 1212, as can be seen in a Bull by Pope Alexander IV from 1258. The privilege elevating it to the status of collegiate church was obtained under Pope Clement VIII in 1592. During the fiefdom of the Cesarini, the need was felt to enlarge and modify the urban layout of the city’s main square, the present-day Piazza della Libertà. The old collegiate church of San Paolo, which a plan by Lauro from 1630 shows as having stood laterally along the square, was demolished in 1734. The first stone of the new church was laid on 10 July 1736 and the works were completed, with the recommencement of worship, in 1753. It was designed by the Milanese architect Pietro Loni and positioned in a vertical direction, with its main entrance facing the square. The civic tower was demolished during the reconstruction and the present clock tower built to the right of the main facade. The new church, with a single nave, preserves a Nativity of Mary by the 16th-century painter Andrea Briotti, a Crucifixion by Durante Nobili and an 18th-century organ attributed to Antonio Callido. The 15th-century baptismal font, formed by a stone traditionally associated with St. Marone resting on a mediaeval capital, is worth seeing. Some of the relics of St. Marone, the city’s patron saint, and those of St. Principius Martyr, which were donated by Duchess Livia Cesarini in 1689, are preserved in the Church of San Paolo.