Cenél nEógain and the Donegal kingdoms, AD 800–1200

Brian Lacey

Cenél nEógain, a royal dynasty from Inishowen in Donegal, defeated its previously more successful opponent, Cenél Conaill – also from Donegal – at the battle of Clóitech in AD 789. All changed following that battle. From then on, the Cenél nEógain kingdom, known as ‘Ailech’, spread across Counties Derry, Tyrone (giving that territory its name), into Armagh, and dominated the whole territory of Ulster. It also attained, alternately, the higher kingship of Tara. After surnames appeared c.1000, the Mac Lochlainns and O’Neills became Cenél nEógain’s leading families. Meanwhile, the defeated Cenél Conaill struggled to maintain some degree of prestige following the emergence of a previously minor, upstart kingdom, originally from west Donegal, the Síl Lugdach. By c.1200 the O’Neills and the leading Síl Lugdach family, the O’Donnells, were in position to rule the whole of Ulster until the English conquest c.1600. This book outlines in detail how that situation came about. 

Brian Lacey, archaeologist/historian, specializes in the north-west of Ireland, AD 500–1200. A former university lecturer, museum director and head of the Discovery Programme (archaeological research institution), he is author of about fifteen books and many research papers.