The Reformation in Ireland was a movement for the reform of religious life and institutions that was introduced into Ireland by the English administration at the behest of King Henry VIII of England. His desire for an annulment of his marriage was known as the King's Great Matter. Ultimately Pope Clement VII refused the petition; consequently it became necessary for the King to assert his lordship over the Roman Catholic Church in his realm to give legal effect to his wishes. In passing the Acts of Supremacy in 1534, the English Parliament confirmed the King's supremacy over the Church in the Kingdom of England. This challenge to Papal supremacy resulted in a breach with the Roman Catholic Church. By 1541, the Irish Parliament had agreed to the change in status of the country from that of a Lordship to that of Kingdom of Ireland.
Unlike similar movements for religious reform on the continent of Europe, the various phases of the English Reformation as it developed in Ireland were largely driven by changes in government policy, to which public opinion in England gradually accommodated itself. In Ireland, however, the government's policy was not embraced by public opinion; the majority of the population continued to adhere to Roman Catholicism.
Norman and English monarchs used the title "Lord of Ireland" to refer to their Irish conquests dating from the Norman invasion of Ireland. In passing the Crown of Ireland Act 1542, the Irish Parliament granted Henry, by his command, a new title - King of Ireland. The state was renamed the Kingdom of Ireland. The King desired this innovation because the Lordship of Ireland had been granted by the Papacy; technically, he held the Lordship in fief from the Pope. As Henry had been excommunicated, he worried that his title could be withdrawn by his overlord - the Pope.
Henry also arranged for the Irish Parliament to declare him the head of the "Church in Ireland". The main instrument of state power in the establishment of the state church in the new Kingdom of Ireland was the Archbishop of Dublin, George Brown. He was appointed by the King upon the death of the incumbent, though without the approval of the Pope. The Archbishop arrived in Ireland in 1536. The reforms were continued by Henry's successor - Edward VI of England. The Church of Ireland claims Apostolic succession because of the continuity in the hierarchy; however this claim is disputed by the Roman Catholic Church, which asserts that only those bishops approved by and in communion with the Holy See are legitimate.