The O'Neill dynasty 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 one of the most prominent family of the Northern Uí Néill, along with the O'Donnell dynasty. Some O'Neills state that their ancestors were kings of Ailech during the Early Middle Ages, as descendants of Niall of the Nine Hostages.