The O'Neill dynasty (Irish: Ó Néill) is a group of families, ultimately all of Irish Gaelic origin, that have held prominent positions and titles in Ireland and elsewhere. As Chiefs of Cenél nEógain, they are historically the most prominent family of the Northern Uí Néill, along with the O'Donnell and O'Doherty. The O'Neills hold that their ancestors were Kings of Ailech during the Early Middle Ages, as descendants of Niall of the Nine Hostages.