Conall Cremthainne also called Conall Err Breg, was an Irish

Ireland

Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...

 king. He was the son of Niall of the Nine Hostages

Niall of the Nine Hostages

Niall Noígíallach , or in English, Niall of the Nine Hostages, son of Eochaid Mugmedón, was an Irish king, the eponymous ancestor of the Uí Néill kindred who dominated Ireland from the 6th century to the 10th century...

, and one of the progenitors of the Uí Néill

Uí Néill

The Uí Néill are Irish and Scottish dynasties who claim descent from Niall Noigiallach , an historical King of Tara who died about 405....

 dynasty.

He is the first king of Uisnech

Uisnech

The Hill of Uisneach, or Ushnagh, also Uisnech , formerly regarded as the centre of Ireland, is a historical site in County Westmeath . The 182 metre hill lies on the north side of the R390 road, 8 km east of the village of Ballymore, beside the village of Loughanavally...

 in Mide from the Ui Neill mentioned in the Book of Leinster king list. His by-name Cremthainne implies fosterage among the Uí Cremthainn of the Airgialla. He was probably originally the same person as Conall Gulban

Conall Gulban

Conall Gulban was an Irish king who founded the kingdom of Tír Conaill in the 5th century, comprising much of what is now County Donegal. He was the son of Niall Noígiallach....

, the distinction arising from 8th century politics.According to a life of Saint Patrick

Saint Patrick

Saint Patrick was a Romano-Briton and Christian missionary, who is the most generally recognized patron saint of Ireland or the Apostle of Ireland, although Brigid of Kildare and Colmcille are also formally patron saints....

 by Tírechán, Patrick blessed Conall and rejected his brother Coirpre mac Néill

Coirpre mac Néill

Coirpre mac Néill . , also Cairbre or Cairpre, was said to be a son of Niall of the Nine Hostages. Coirpre was perhaps the leader of the conquests that established the southern Uí Néill in the midlands of Ireland. The record of the Irish annals suggests that Coirpre's successes were reattributed to...

, ancestor of the Cenél Coirpri, at a meeting at Tailtiu. Nothing is recorded of him in the annals other than his death date.

Through his son Fergus Cerrbél, he was the ancestor of the Clann Cholmáin

Clann Cholmáin

Clann Cholmáin is the name of the dynasty descended from Colmán Mór , son of Diarmait mac Cerbaill. Part of the Southern Uí Néill — they were the kings of Mide — they traced their descent to Niall Noígiallach and his son Conall Cremthainne.Related dynasties descended through Conall...

 and Síl nÁedo Sláine

Síl nÁedo Sláine

Síl nÁedo Sláine is the name of the descendants of Áed Sláine , son of Diarmait mac Cerbaill. Part of the Southern Uí Néill—they were the kings of Brega—they claimed descent from Niall Noígiallach and his son Conall Cremthainne....

. Another son was Ardgal mac Conaill

Ardgal mac Conaill

Ardgal mac Conaill was a King of Uisnech in Mide of the Ui Neill dynasty. He was the son of Conall Cremthainne and grandson of Niall Noígíallach...

(died 520) was ancestor of the Cenél nArdgail in Co.Meath