Their descendants were known as the northern Hy Neill.'
Diarmait, son of Fergus Cerbaill (544-565), of the southern Hy Neill, undoubtedly professed Christianity though he still clung to many pagan practices, such as polygamy and the use of druidical incantations in battle.
St Columba's kinsmen, the northern Hy Neill, took up the quarrel, and attacked and defeated the king at Culdreimne in 561.
Others have surmised that it was abandoned as a regular place of residence long before this, soon after the northern and southern branches of the Hy Neill had consolidated their power at Ailech and in Westmeath.
Aed, son of Ainmire (572-598) of the northern Hy Neill, figures prominently in the story of St Columba.