From jocus came Jodocus, an Armorican prince, belonging to a family which migrated from Wales.  He refused the sovereignty of Brittany, to live as a hermit in Ponthieu, where he is still remembered as St. Josse, and named at least three villages, perhaps also forming Josselin; but in his native Brittany, Judicael, an old princely name, seems to have been the form of his commemoration. (Yonge)