RTÉ crew visits Dún Briste, separated by St Patrick from the mainland.

The legend of St Patrick's confrontation with the pagan god Cromduff is told by Patrick Caulfield, father of archaeologist Séamus Caulfield. After finishing his 40-day fast on Croagh Patrick, the saint made his way to Downpatrick Head in Co. Mayo to visit local pagan chieftain Cromduff. Two dogs were sent to attack St Patrick, but instead they lay down and licked his feet. Patrick then attempted to convert Cromduff to Christianity. When he failed, he struck the ground with his crozier and it separated from the mainland, creating the sea stack, Dún Briste, where Cromduff later perished.