What is "illtud"

St. Illtud (also spelled Illtyd, Eltut, and, in Latin, Hildutus), also known as Illtud Farchog "Illtud the Knight", is venerated as the founder- abbot and teacher of the divinity school known as Cor Tewdws, located in Llanilltud Fawr (Llantwit Major) in the Welsh county of Glamorgan. He founded the monastery and college in the 6th century, and the school is believed to be Britain’s earliest centre of learning. At its height, it had over 1000 pupils and schooled many of the great saints of the age, including Saint Patrick of Ireland, Saint David of Wales, Gildas the Historian, and Samson of Dol.