Saint Cewydd was a pre-congregational saint of Wales in the Early Middle Ages (6th century). He is known as the Welsh 'Rain Saint', like Medard in France, Gildas in Brittany and Swithin in England. It would appear that a pre-Christian rain day might have been associated with a date in July, when, if it rained on that day, it was believed rain would continue for forty days. Ecclesiastical records in the Book of Llandaff refer to a religious establishment of lann ceuid, probably at Lancaut, which is likely to have been established by 625AD and was recorded there by 703AD.