The medieval lists give Ireland thousands of years of high kings in an unbroken line from Tara. Most of that line is legend. This page goes down it in order and marks where the legend ends and the history starts.
Medieval and early modern Irish writing gives Ireland an almost unbroken line of high kings ruling from the Hill of Tara, over a hierarchy of lesser kings, going back thousands of years. The title was attached to historical kings, and also backdated to earlier ones and given to legendary figures who never held it.
Niall Noígíallach, of the nine hostages, is legendary and possibly historical. He is the ancestor of the Uí Néill dynasties who dominated Ireland from the 6th to the 10th century. The annals put his reign in the late 4th and early 5th centuries; modern scholars date him about half a century later.
For four centuries the high kingship was, in practice, the property of Niall's descendants. In 919 the returned Dublin Norse killed the high king Niall Glúndub and five other kings at Islandbridge.
King of Mide and high king, sometimes anglicised as Malachy. His victory over Olaf Cuaran at the Battle of Tara in 980 brought the Norse kingdom of Dublin under Gaelic Irish control.
Brian Bóruma of the Dál gCais, king of Munster, took the high kingship in 1002 when Máel Sechnaill yielded to him, and ended the Uí Néill hold on it. He was killed at the Battle of Clontarf on Good Friday, 23 April 1014, though his army won.
Rory O'Connor, king of Connacht, the last high king before the Anglo-Norman invasion. By the Treaty of Windsor in 1175 he kept Ireland outside Leinster, Dublin and the country around Waterford, provided he paid tribute and fealty to Henry II.
The Gaelic kings offered Brian O'Neill the high kingship in 1258. The attempt died with him at Downpatrick in 1260, and nobody claimed the title again.
Nobody can say. The medieval lists run back thousands of years from Tara, but the early names are legendary, and the title was backdated to kings who never held it. Niall of the Nine Hostages, in the 5th century, is where the line begins to touch history, and even he is only possibly historical.
Ruaidrí Ua Conchobair, Rory O'Connor, high king from 1166 to 1198, the last before the Anglo-Norman invasion. The Gaelic kings offered the title to Brian O'Neill in 1258, but he was killed at Downpatrick in 1260.
Yes, from 1002 to 1014. He broke the Uí Néill hold on the title and was killed at the Battle of Clontarf on 23 April 1014, though his side won the battle.
Possibly. He is described as legendary and possibly historical, the ancestor of the Uí Néill. The annals place him in the late 4th and early 5th centuries; modern scholars put him about fifty years later.
The Cycles of the Kings: the stories told about them · The full timeline · County Meath and Tara · The eras of Irish history