Religion in the Republic of Ireland
The predominant religion in the Republic of Ireland is Christianity, with the largest church being the Roman Catholic Church. The Irish constitution says that the state may not endorse any particular religion and guarantees freedom of religion.
Normans in Ireland
There was no religious division in medieval Ireland, beyond the requirement that English-born prelates should run the Irish church. After the Henrician Reformation of the 1530s, however, most of the pre-16th century inhabitants of Ireland continued their allegiance to Roman Catholicism, even after the establishment of the Anglican Church in England, and its Irish counterpart, the Church of Ireland.