It was the time when the Britons left their island, before the Saxon invaders to win Armorica. Winwalloë, son of Lady Gwen and a notable Welsh, was born near Saint-Brieuc. He was assigned to St. Budoc holding a monastic school on the island Lavret (Bréhat archipelago). At 24, St. Patrick of Ireland appears to him and asked him to found a new monastery. It starts with 11 companions and fixed first on the island Tibidi the bottom of the harbor of Brest, and on the opposite bank of Alder in Lantowinnoc, Landévennec now. After his death, his cult spread in Brittany and Cornwall UK. In the abbey of Landévennec, the monks did not fail to invoke every night "Holy father Guénolé." Numerous parishes of Britain are under his patronage especially Batz-sur-Mer.