sentences:  Around 500, Illtud, founded a monastery called Cor Tewdws at Llanilltud Fawr.Its school was a primary learning center of Sub-Roman Britain, but was situated on the Glamorgan Plain exposed to hostile incursions from Irish pirates, and to Viking raids.The course of studies at Llaniltyd (and this also applies to the other monasteries) included Latin, Greek, rhetoric, philosophy, theology, and mathematics.