Gurthiern was a Welsh prince, born in Cambria around 450, who later lived as a hermit in Brittany. He is recognized as the founder of an abbey located at Quimperlé. As a figure honored in both Catholic and Orthodox traditions, he is commemorated as a saint. His life and religious contributions are documented in the *Vita sancta Gurthierni*, which details his transition from royalty to a life of asceticism.