Cellach mac Cerbaill

Cellach mac Cerbaill (nicknamed Cellach of the Hard Conflicts) was king of Osraige from 905 to his death in 908.

A panel on the base of the North Cross at Ahenny, County Tipperary (on the border of Munster and Osraige) depicts a funeral procession, sometimes supposed to be that of Cormac mac Cuilennáin after the battle in which he and king Cellach mac Cerbaill were killed.

Ceallach was a son of king Cerball of Osraige. He took part in the battle of Gowran in 893. He came to the throne after the deposition of his older brother Diarmait in 905. Along with his son Muircheartach, he was slain in the battle of Mag Ailbe fighting on the side of the illustrious king-bishop of Cashel Cormac mac Cuilennáin in 908. The Annals of Inisfallen record his death in 908:

However, the Annals of the Four Masters state that this conflict was called the Battle of Bealach-Mughna and assign it to have taken place in 903:

His brother Diarmait was afterwards reinstated to the throne by their first cousin, high king Flann Sinna.

He was ancestor of the later medieval Mac Giolla Phádraig family, and the Icelandic Landnámabók (in which he is called Kjallakr Kjarvalson) names him as an ancestor of some of Iceland's early settlers.