St Patrick's Cathedral, Dublin
Saint Patrick's Cathedral () in Dublin, Ireland, founded in 1191, is the National Cathedral of the Church of Ireland. With its spire, St. Patrick's is the tallest church (not Cathedral) in Ireland and the largest. Christ Church Cathedral, also a Church of Ireland cathedral in Dublin, is designated as the local Cathedral of the diocese of Dublin and Glendalough.
Cathedral of Saint Mel in Ardagh
The Cathedral of Saint Mell is the name given to the ruins of a small, Early Medieval church in the village of Ardagh, County Longford in Ireland, not to be confused with St Mel's Cathedral in the town of Longford. Church reform in the 12th century made Saint Mel's Cathedral in Ardagh the centre of the Diocese of Ardagh and Clonmacnoise, demonstrating the importance of the site as a Cathedral and bishopric see. Although known as Saint Mel's Cathedral, the ruined church dates from three centuries after the saint's death, and predates the introduction of a diocesan system in Ireland.