Gildas (ca. 500–ca. 570) was a monastic leader who influenced the development of monasticism in Ireland through his Irish disciples, a visit to Ireland, and subsequent correspondence with Irish monasteries. Born in Scotland, he became a monk probably after being married and widowed. His famous work, De excidio Britanniae (“On the Ruin of Britain”), cited by the Venerable Bede [May 25], described the decadence of contemporary British secular rulers and clerics and placed on them the blame for the victory of the Anglo-Saxon invaders. He founded a monastery on an island in Brittany’s Morbihan Bay that became the center of his cult. It is still known as the “island of monks.” His feast does not appear on the General Roman Calendar.