St Patrick's Cathedral is a Church of Ireland cathedral in Armagh, Northern Ireland. It is the seat of the Anglican Archbishop of Armagh and Diocese of Armagh. The origins of the site are as a 5th-century Irish stone monastery, said to have been founded by St. Patrick. Throughout the Middle Ages, the cathedral was the seat of the Catholic Archbishop of Armagh, head of the Catholic Church in Ireland, and one of the most important churches in Gaelic Ireland. With the 16th-century Protestant Reformation, the cathedral was retained by the Protestant Church of Ireland. It is one of two Anglican churches in Armagh City, with the other being St Mark's Parish Church.