But, after seven years, he resigned, left, with eleven other monks, first for the Channel Islands, then for Brittany, from there to Ireland to study the monastic life practiced there according to the rule of Columbanus.

He probably landed in Armorican Cornwall, founded three monasteries, and considered going to Groix to inspect some small monastic establishments.

He stayed there for a few years, then finally landed on the right bank of the Blavet, where the Saint-Guenaël chapel is today, in Lanester.

The hunters, amazed, went to tell their master Waroch, Count of Vannes, who came to visit him, trying to persuade him to stay with him at court.

The saint's name is composed of the Breton elements gwenn "white, fair; blessed" and hael "generous".

The surnames Guénal, Guénel, Trévinal and Kervennal doubtless have a connection with this saint's name, either directly or through a place name, such as the examples above.