Dedicated to Saint Colomba (a martyr, originally from France, who was venerated mostly by the common people), this church was consacrated and became a cathedral in 1154.
In the Medieval period, after some restoration and transformation, it became the hub of city life; the splendour and the solemnity of its architectural lines make this the most prestigious building of the period.
The bell tower was built in the 13th century and used to house the sacristy.
Unfortunately, today the recently restored bell tower is all what remains of the ancient cathedral.