This cathedral sits on a site that was originally a palace belonging to one of the kings of Munster, Donal Mor O'Brien, who donated the land to the church in 1172. The current building is much newer than that, but still contains a 12th-century Romanesque doorway, a pre-Reformation stone altar, and a huge stone slab said to be the coffin lid of Donal Mor O'Brien's grave. It also has original 15th-century misericords (supports for standing worshippers).