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
Changing religion, or rather conforming to the State Church, was always an option for any of the King of Ireland's subjects, and an open avenue to inclusion in the officially recognised "body politic", and, indeed, many Old English such as Edmund Burke were newly-conforming Anglicans who retained a certain sympathy and understanding for the difficult position of Roman Catholics, as Burke did in his parliamentary career. Others in the gentry such as the Viscounts Dillon and the Lords Dunsany belonged to Old English families who had originally undergone a religious conversion from Rome to Canterbury to save their lands and titles. Some members of the "Old English" who had thus gained membership in the Irish Ascendancy even became adherents of the cause of Irish independence. Whereas the Old English FitzGerald Dukes of Leinster held the premier title in the Irish House of Lords when it was abolished in 1800, a scion of that Ascendancy family, the Irish nationalist Lord Edward Fitzgerald, was a brother of the second duke.