Monarchical systems of government have existed in Ireland from ancient times. In most of Ireland, this continued until 1949, when it transitioned to being the Republic of Ireland. Northern Ireland, as part of the United Kingdom, remains under a monarchical system of government.
The office of High King of Ireland effectively ended with the Norman invasion of Ireland (1169–1171) in which the island was declared a fief of the Holy See under the Lordship of the King of England. In practice, conquered territory was divided amongst various Anglo-Norman noble families who assumed title over both the land and the people with the prior Irish inhabitants being either displaced or subjugated under the previously alien system of serfdom. Though the revolutionary change in the status quo was undeniable, the Anglo-Norman invaders would fail to conquer many of the Gaelic kingdoms of Ireland, which continued to exist, often expanding for centuries after, however none could make any viable claims of High Kingship. This lasted until the Parliament of Ireland conferred the crown of Ireland upon King Henry VIII of England during the English Reformation. Henry initiated the Tudor conquest of Ireland which ended Gaelic political independence from the English monarch who now held the crowns of England and Ireland in a personal union.
The Union of the Crowns in 1603 expanded the personal union to include Scotland. The personal union between England and Scotland became a political union with the enactments of the Acts of Union 1707, which created the Kingdom of Great Britain. The crowns of Great Britain and Ireland remained in personal union until it was also ended by the Acts of Union 1800, which united Ireland and Great Britain into the United Kingdom of Great Britain and Ireland in January 1801.
In December 1922, most of Ireland seceded from the United Kingdom, becoming the Irish Free State; at the same time, the newly created Northern Ireland, which covered most of Ulster, remained part of the United Kingdom. As a dominion within the British Empire, the Free State legally retained the same person as monarch as the United Kingdom-which in 1927 changed its name to the United Kingdom of Great Britain and Northern Ireland. In 1937, the Free State adopted a new constitution that removed all mention of the monarchy. In April 1949, the former Free State, which covered most of Ireland, declared itself a republic, and withdrew from the Commonwealth of Nations; this left Northern Ireland as the only part of the island that retained a monarchical system.
Gaelic kingdoms
Gaelic Ireland consisted of as few as five and as many as nine Primary kingdoms (Cúicide/Cóicide 'fifths') which were often subdivided into many minor smaller kingdoms (Tuatha, 'folkdoms'). The primary kingdoms were Ailech, Airgíalla, Connacht, Leinster, Mide, Osraige, Munster, Thomond and Ulster. Until the end of Gaelic Ireland they continued to fluctuate, expand and contract in size, as well as dissolving entirely or being amalgamated into new entities. The role of High King of Ireland was primarily titular and rarely (if ever) absolute. Gaelic Ireland was not ruled as a unitary state.
The names of Connacht, Ulster, Leinster and Munster are still in use, now applied to the four modern provinces of Ireland. The following is a list of the main Irish kingdoms and their kings: Kings of Ailech (5th century to 1185) Kings of Airgíalla (?-1590) Kings of Connacht (406–1474) Kings of Leinster (634 to 1603 or 1632 (de facto)) Kings of Mide (8th–12th centuries) Kings of Osraige (to 12th century) Kings of Munster (4th century to 1138 or 1194 (claimant)) Kings of Thomond (1118–1543) Kings of Ulster (5th–12th centuries)
Ard Rí co febressa: High Kings with opposition
Máire Herbert has noted that "Annal evidence from the late eighth century in Ireland suggests that the larger provincial kingships were already accruing power at the expense of smaller political units. Leading kings appear in public roles at church-state proclamations ... and at royal conferences with their peers." (2000, p. 62). Responding to the assumption of the title ri hErenn uile ("king of all Ireland") by Mael Sechlainn I in 862, she furthermore states that
Nevertheless, the achievements of Máel Sechlainn I and his successors were purely personal, and open to destruction upon their deaths. Between 846 and 1022, and again from 1042 to 1166, kings from the leading Irish kingdoms made greater attempts to compel the rest of the island's populace to their rule, with varying degrees of success, until the inauguration of Ruaidri Ua Conchobair (Rory O'Connor) in 1166,