There he learned how to live an ascetic life, and was ordained by St. Bishop Dubricius, at which event a white dove descended onto his shoulder. Samson left the monastery when two nephews of Illtud who envied him tried to slander him; they fed him poison, which had no effect.
He started traveling. He founded a community in Cornwall, he went to the Scilly Isles where the island of Samson is named for him, then to Guernsey where he is the patron saint. In Brittany, he found the monastery of Dol.
While in Brittany, he became involved in local politics. There was a king, Conomor, who was serving as regent for a nephew whom he tried to have killed. Samson, along with Gildas and others, persuaded the local bishops to excommunicate Conomor. Samson also persuaded King of the Franks Childebert I to stop supporting Conomor's position as "protector of the English Channel."
We know the date when he was ordained, because it is recorded as taking place on the Feast of the Chair of St. Peter (22 February) at the beginning of Lent. For February 22 to be at the beginning of Lent (a "floating" holiday), it would have to take place in 521. Traditionally, one was ordained at the age of 35, which would mean he was born in 486. Samson attended a religious council in Paris which took place sometime between 556 and 573, at which time he would have been already quite old. His signature is on documents from it as "Samson, a sinner." The estimated date of his death is halfway between the estimates of the date of the Paris council. He was buried in the Cathedral of Dol.
But about this Conomor character: he is thought to be the historical foundation for the folk tale of Bluebeard, and of the wife-beating giant Cormoran, and Tristan's uncle. How bad could he be to inspire three vile characters of legend? We'll find out tomorrow.