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. 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. However, a number of factors complicated the adoption of the religious innovations in Ireland; the majority of the population there adhered to the Latin Rite of the Church.

Religious policy of Henry VIII:

Henry had arranged to be declared head of the "Church in Ireland" through an Act of the Irish Parliament. Norman and English monarchs used the title "Lord of Ireland" to refer to their position in the conquered lands on the island of Ireland. The title was changed by the Crown of Ireland Act passed by the Irish Parliament in 1541, when on Henry's demand, he was granted a new title, King of Ireland, with the state renamed the Kingdom of Ireland. The King changed his title because the Lordship of Ireland had been granted to the Norman monarchy by the Papacy; technically, he held the Lordship in fief from the Pope. As Henry had been excommunicated by the Catholic Church, he worried that his title could be withdrawn by the Holy See. 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.

Dissolution of the monasteries:
The dissolutions in Ireland followed a very different course from those in England and Wales. There were around 400 religious houses in Ireland in 1530-many more, relative to population and material wealth than in England and Wales. In marked distinction to the situation in England, in Ireland the houses of friars had flourished in the 15th century, attracting popular support and financial endowments, undertaking many ambitious building schemes, and maintaining a regular conventual and spiritual life. They constituted around half of the total number of religious houses. Irish monasteries, by contrast, had experienced a catastrophic decline in numbers, such that by the 16th century, it appears that only a minority maintained the daily religious observance of the Divine Office. Henry's direct authority, as Lord of Ireland, and from 1541 as King of Ireland, only extended to the area of the Pale immediately around Dublin. From the late 1530s his administrators temporarily succeeded in persuading some clan chiefs to adopt his policy of surrender and regrant, including the adoption of his state religion.

Nevertheless, Henry was determined to carry through a policy of dissolution in Ireland - and in 1537 introduced legislation into the Irish Parliament to legalise the closure of monasteries. The process faced considerable opposition, and only sixteen houses were suppressed. Henry remained resolute however, and from 1541 as part of the Tudor conquest of Ireland, he continued to press for the area of successful dissolution to be extended. For the most part, this involved making deals with local lords, under which monastic property was granted away in exchange for oaths of allegiance to the new Irish Crown; and consequently Henry acquired little if any of the wealth of the Irish houses. By the time of Henry's death (1547) around half of the Irish houses had been suppressed; but many houses of friars continued to resist dissolution until well into the reign of Elizabeth I.

Henry's son Edward VI of England (1547-53) formally established Protestantism as the state religion, which was as much a religious matter as his father's reformation had been political. His reign only lasted for six years and his principal reform, the Act of Uniformity 1549, had much less impact in Ireland than in England.

Religious Policy of Queen Mary I:
Henry's and Edward's efforts were then reversed by Queen Mary I of England (1553-1558), who had always been Roman Catholic. On her ascent to the throne, Mary reimposed orthodox Catholicism. During her reign, it was agreed under the Treaty of Augsburg in 1555 that European subjects should follow the official faith espoused by their rulers (in Latin, 'Cuius regio, eius religio'). She married the future King Philip II of Spain. When some Episcopal sees in Ireland became vacant, clerics loyal to Rome were chosen by Mary, with the approbation of the Pope. In other cases, bishops in possession of dioceses that had been appointed by her father, without the approval of the Pope, were deposed. She arranged for the Act of Supremacy (which asserted England's independence from papal authority) to be repealed in 1554. In turn it was agreed that the monasteries would stay dissolved so as to preserve the loyalty of those who had bought monastic lands. In Ireland Mary started the first planned wholesale plantations of settlers from England which, ironically, soon came to be associated with Protestantism.

Religious Policy of Queen Elizabeth I:

Mary's half-sister, Queen Elizabeth I succeeded in having Parliament pass another Act of Supremacy in 1559. The Act of 1534 had declared the English crown to be 'the only supreme head on earth of the Church in England' in place of the pope. Any act of allegiance to the latter was considered treasonous because the papacy claimed both spiritual and political power over its followers.

Additionally, the Act of Uniformity, passed in 1560, made worship in churches adhering to the Church of England compulsory. Anyone who took office in the English church or government was required to take the Oath of Supremacy; penalties for violating it included hanging and quartering. Attendance at Anglican services became obligatory - those who refused to attend Anglican services, whether Roman Catholics or Puritans, could be fined and physically punished as recusants by the civil powers. Initially Elizabeth had tolerated non-Anglican observance, but worried about the political aspect of Roman Catholicism after the Papal Bull Regnans in Excelsis was promulgated in 1570.

The issue of religious and political rivalry continued during the two Desmond Rebellions (1569-83) and the Nine Years' War (1594-1603), both of which overlapped with the Anglo-Spanish War (1585-1604), during which some rebellious Irish nobles were helped by the Papacy and by Elizabeth's arch-enemy Philip II of Spain. Due to the unsettled state of the country Protestantism made little progress, unlike in Celtic Scotland and Wales at that time. It came to be associated with military conquest and was therefore hated by many. The political-religious overlap was personified by Adam Loftus, who served as Archbishop and as Lord Chancellor of Ireland. An unlikely alliance formed between Gaelic Irish families and the Norman "Old English", who had been enemies for centuries but who now mostly remained Roman Catholic.

During her reign the New testament was translated into Irish for the first time, by Nicholas Walsh, Bishop of Ossory until his murder in 1585, and then by Archbishop Nehemiah Donnellan, and was published in 1602. Another translation of the Gospels was sponsored by Richard Boyle. She also founded Trinity College Dublin, Ireland's first university, in 1592.

Religious Policy of King James I:

The reign of James I (1603-25) started tolerantly, and the Treaty of London (1604) was signed with Spain, but the Gunpowder Plot in 1605 caused him and his officials to adopt a harder line against Roman Catholics who remained in the majority, even in the Irish House of Lords. So few converted to Protestantism that the Catholic Counter-Reformation was introduced in 1612, much later than in the rest of Europe. The Flight of the Earls in 1607 led on to the Plantation of Ulster, but many of the new settlers were Presbyterian and not Anglican; reformed, but not entirely acceptable to the Dublin administration. The settlers allowed James to create a slight Protestant majority in the Irish House of Commons in 1613.

The work of translating the Old Testament into Irish for the first time was undertaken by William Bedell (1571-1642), Bishop of Kilmore, who completed his translation within the reign of Charles I, although it was not published until 1680 in a revised version by Narcissus Marsh (1638-1713), Archbishop of Dublin. Bedell had undertaken a translation of the Book of Common Prayer published in 1606.

Policies of Commonwealth and Restoration regimes:

The final stage was marked by the Irish Rebellion of 1641 by those groups of the Irish nobility that continued in their loyalty to the crown, Catholicism or both. The Cromwellian conquest of Ireland in 1649-53 briefly introduced Puritanism as the state religion. The Restoration period that followed and the brief reign of the Catholic James II were characterised by unusual state tolerance for religions in their kingdoms. In the Williamite War in Ireland that followed, absolutism was destroyed but the majority of the population felt more conquered than ever. The Irish parliament introduced a series of "Penal Laws" with the ostensible purpose of displacing Catholicism as the majority religion. However, there was no real by the Protestant Ascendancy to actively convert the bulk of the population to Anglicanism which suggests that their main purpose was economic - to transfer wealth from Catholic hands to Protestant hands.

An Irish translation of the revised Book of Common Prayer of 1662 was effected by John Richardson (1664-1747), and was published in 1712.

Despite the Reformation's damaging association with military conquests, some Irish Anglican clerics were outstanding philosophers, such as James Ussher, Jonathan Swift, John Toland and George Berkeley. The Presbyterian philosopher Francis Hutcheson (1694-146) had a notable impact in Colonial America.