The earliest records date back to the thirteenth century (the first written document that talks about it dates back to 1252), and was most probably built on the ruins of earlier fortifications of the city.
The first reconstruction of the basilica began in 1596 and continued at different stages until 1774, when the building was equipped with a neoclassical facade, with triangular pediment and six Ionic pilasters. In the nineteenth century it was thought to a substantial expansion of the church. The current appearance was designed by Giuseppe Bovara who worked there from 1831 to 1862. The facade was finished rather later, in 1881-83, and the neo-Gothic bell tower, erected on a Spanish bastion, dates from 1902-04.
96 meters high, the tower has over time become the symbol of the city.
The interior is decorated with frescoes with scenes evangelical bishops and forty medallions of saints. As a result of restoration work carried out in the sixties of the twentieth century, emerged pictorial fragments of the late fourteenth and early fifteenth century. The Chapel of the Baptistery is the only remaining part of the original thirteenth-century church, and the font contained therein dating back to 1596.