St Mary's Pro-Cathedral or simply the Pro-Cathedral, originally uploaded by infomatique.
The city of Dublin possesses two cathedrals, but unusually, both belong to the minority Church of Ireland, which up until 1871 had been the religion of establishment in Ireland. In contrast, the majority religion in Ireland, Roman Catholicism, has no cathedral in Ireland's capital city and has not had one since the Reformation, when the bishops in Ireland followed Henry VIII's break from Rome. As the official church, the Church of Ireland took control of most church property, including the Cathedral of the Holy Trinity (generally known as Christchurch) and St. Patrick's Cathedral. These two churches had long shared the role of cathedral of Dublin, controversially at first, then under an agreement of 1300, Pacis Compositio, which gave Christchurch formal precedence, including the right to enthrone the Archbishop and to hold his cross, mitre and ring after death, but with deceased Archbishops of Dublin to be buried alternately in each of the two cathedrals, unless they personally willed otherwise, and the two cathedrals to act as one, and "shared equally in their freedoms".
Even though Christchurch has been the property of the Anglican church for nearly five hundred years, it is still viewed by the Roman Catholic Church and the Pope as the primary official Dublin cathedral, since it was so designated by the pope at the request of the then Archbishop of Dublin, St. Laurence O'Toole in the 12th century. Until the pope either formally revokes Christchurch's designation (which, given its historic status and significance for Dubliners, is unlikely), or grants cathedral status to another church (which is much more likely), the main Roman Catholic church in Dublin will continue to be the "pro-cathedral" (meaning in effect acting cathedral), a title officially given to St Mary's Church in 1886, though it used that title unofficially since the 1820s.