 The initial ascent of Ailech had coincided with the decline of the Ulaid, whose kingdom of Ulster receded to the north-east coast.In the 12th century the kingdom of Ailech split into two sovereign territories and Cenél nEógain became Tír Eoghain, the land of Eoghan, Anglicised as Tyrone.It was ruled under the Meic Lochlainn clan and then under their kinsmen the Ó Néill clan.