He was born to a prominent noble family, the Ui-Niall clan of Ireland, but he forsook all worldly things and became a monk at a young age. He founded the monasteries of Derry and Durrow, and traveled as a missionary in Ireland for almost twenty years. In 565 he settled on the island of Iona, off the coast of Scotland; there he remained for 32 years, establishing the famous monastery of Iona and continuing in his missionary labors. He reposed in peace at Iona.