EXTERIOR
The basilica is built as a rectangle. The gargoyles featuring monks, devils and various monstrous animals with some swallowing men surround three sides of the building. Some of these gargoyles protrude as much as 1.50m from the walls. The façade is asymmetrical which is characteristic of the Breton style. It is essentially composed of two gables. The whole building is dominated by a spire, some 60 metres high, of pure hard Breton granite. It holds a bell of nearly 5000 kilos which lends its weight to ceremonious occasions.
THE CENTRAL NAVE
Like many Gothic naves, the Quire of the church is situated to the left and is not found exactly at the axis of the central aisle. The big stained glass window at the end immediately attracts your attention. This window dates back to the 19th century. It represents the mysteries of the rosary with the portraits of the family de Rohan at the bottom, who have over the centuries contributed to the building and decoration of this church. Also dating from the 19th century is the base of the main alter which is made of granite from Lannion and marble from Carrare. It is flanked on the right with the elegant piscina of stone from the end of the 15th century and on the left a tabernacle from the 16th century decorated with cherubs. The arched Quire was built in the 13th century. It is a magnificent example of ribbed arches. These run into short columns moulded into the wall and supported by men’s heads.
To the left of the Quire three short fat pillars are the only relics left of the Norman church; rebuilt after the destruction by Henry II, Henry Plantagenet in the 12th Century. The ceiling, although well altered gives an idea of Norman sculptures in Brittany at this time. The designs are very varied. The frise unwinds principally with animals and vegetables. There are oak leaves, crooks, geometrical figures, much used in Celtic art. Also a dog which is the only example known in Brittany according to the historian Roger Grand. Olivier de Clisson commissioned the reconstruction of the central nave. The two arches were finished in the 14th century.
Right at the back of the church above the door, you must not miss the notable casing of the organ from the 17th century. The organ itself plays 20 remarkable tones and is signed LEHELLOCO 1674. This organ was restored in 1990.
Finally you can admire the pulpit; the masterpiece of a local iron craftsman Eustcache Roussin. It dates from the 18th century. The banisters are admirable, it is a representation of the four gospels.


THE NORTH WAVE
Completed in 1491, it underwent important renovations at the end of the 19th century and the beginning of the 20th century. The clock tower was abolished and the foundations and opening in the east wall were converted into the Chapel of Notre Dame du Roncier, formerly, the Chapel Sainte-Catherine.
The transept of the nave is illuminated by the stained glass window donated by the Duc Montmorency-Perigord in memory of his wife, Anne de Rohan-Chabot. It represents courage in battle. The piece is remarkable in both composition and colour. It is signed by Gruber and was installed in 1932.

THE SOUTH NAVE
The south nave is the narrowest in the far right. It was completed around 1470, the same time as the central nave. Olivier de Clisson erected the chapel Sainte Marguerite, the name of his second wife, Marguerite de Rohan. Clisson reserved the chapel for his use and it was separated from the Quire by a fine grill of granite, behind which he would attend Mass. This grill is an amazing stone lace.
When he died in Josselin, Oliver de Clisson was laid to rest next to Marguerite as was his wish. They constructed a tomb which was originally in the Quire. It was desecrated during the Revolution (the figures were decapitated and the bones scattered). In 1856 the cenotaph was restored and transferred to the Chapel Sainte Marguerite.
