The oldest portions of the Cathedral date from the 13th century.
The nave, completed in the 14th century, has eight bays. At the fourth bay it is flanked by two square towers.
The northern tower, called the “Mutte” Tower, contains the town-bell. It is surmounted by a fine spire, from which there is an extensive view of the surrounding country. It was there that the city watchman was installed, whose duty it was to give the alarm in case of fire. On the other side of the nave stands the Chapter Tower, which was finished in 1839. There is a fine doorway at the foot of each tower.
Another, smaller polygonal tower, called the Clock Tower, is built over the southern aisle.
On each side of the choir, where it meets the arms of the transept, are the two small “Charlemagne” towers, so called in memory of those which existed in the romanesque building. They give access by spiral stairways to the outside terraces over the Cathedral.
While the nave is 13th century the transept dates from the 15th, and the choir, built over a great sepulchral crypt, is contemporary with the last Gothic period.
Although completed in 1546 the Cathedral later underwent many alterations. Fires necessitated repairs, and in 1753, by order of the Governor (Marshal de Belle-Isle), the laying out of a square in front of the Cathedral necessitated the demolition of the outbuildings of the bishop’s house and the erection of a portal.
