On 9 May 1726 another storm hit the town and sent the rest of the tower tumbling, crushing half of the nave and part of the choir.

Good progress was made with the first stone being laid on the 18 September 1727 and ten years later inauguration of the major part of the cathedral was possible.

The choir area comprises three crossings, a painting, columns of black marble supporting a curvilinear corniche above which is another niche.

The main altar shaped like a tomb in white marble and dating to the 19th century is surmounted on each side by adoring angels.

In this chapel is a reliquary in the form of a cross and made in cast iron, as well as a stone statue dating to the 18th-century of "Notre-Dame de Délivrance".

[2] [4] Given the presence in the church of some bone fragments of Saint Patern, a visit to the church was one of the seven stages of this pilgrimage so popular in the Middle Ages, the task for the pilgrim was to visit the tombs of the seven founding saints of Brittany, the ancient bishops Brieuc, Malo, Samson, Corentin, Pol, Tugwal and Patern in Vannes.