The O'Neill dynasty (Irish: Ó Néill) are a lineage of Irish Gaelic origin that held prominent positions and titles in Ireland and elsewhere. As kings of Cenél nEógain, they were historically the most prominent family of the Northern Uí Néill, along with the O'Donnell dynasty. The O'Neills hold that their ancestors were kings of Ailech during the Early Middle Ages, as descendants of Niall of the Nine Hostages. Two of their progenitors were High Kings of Ireland, Niall Glúndub (from whom they take their name) and Domnall ua Néill. From 1232 until 1616, the O'Neill were sovereign kings of Tír Eógain, holding territories in the north of Ireland in the province of Ulster; particularly around modern County Tyrone, County Londonderry and County Antrim, in what is now Northern Ireland. After their realm was merged with the Kingdom of Ireland and the land was caught up in the Plantation of Ulster, they were involved in a number of significant events, such as Tyrone's Rebellion, the Flight of the Earls, the Irish Rebellion of 1641 and the Irish Confederate Wars. Naming conventions Origins The O'Neill lineage claims descent from Niall Glúndub, a 10th-century king of Ailech as well as High King of Ireland. Niall descended from the Cenél nEógain branch of the Northern Uí Néill. The first to adopt the patronymic surname was Niall Glúndub's great-grandson, Flaithbertach Ua Néill. The lineage does not receive a mention in non-Irish recorded history sources between the 1080s and 1160s, from which they emerge from a "very murky background". In 1167, King of Ireland Ruaidrí Ua Conchobhair marched north and divided the kingdom of Ailech into two. The portion north of Slieve Gallion, was given to Niall Mac Lochlainn (McLaughlin), with the portion south of Slieve Gallion, given to Áed Ua Néill. After this the two rival dynasties contested for control over Tír Eoghain until the battle of Caimeirge in 1241, where the O'Neills wiped out the MacLoughlin leadership. O'Neills of Tyrone After 1241, the O'Neill lineage dominated and displaced other lineage, using the disruption of the Norman invasion of Ireland in 1169 to their benefit and were able to consolidate. The Bruce Invasion of Ireland devastated the Norman Earldom of Ulster, which held sway over eastern Ulster and most of its north coast all the way to Derry. Its collapse in 1333 allowed a branch of the O'Neill that had been on good terms with