• 3 July
• Prince who became a hermit in Brittany. The local lord, Grallon, gave Gunthiern land on the Isle of Groie, near River Blavet to found a monastery. It survives today as the Benedictine house of Kemperle.
• Legend says that insects once threatened to destroy the region’s crops. Count Guerech I of Vannes, France, requested the saint‘s help. Gunthiern blessed some water and had it sprinkled over the fields. The insects fled, and the crops were saved.
• c.500 in Brittany (in modern France) of natural causes
• his body was hidden during the Norman invasions, and was lost for a while
• remains re-discovered in the 11th century
• relics were translated to the Kemperle monastery