In 563 he left his native land, accompanied by twelve disciples, and went on a mission to northern Britain, perhaps on the invitation of his kinsman Conall, king of Dalriada.
Columba was honoured by his countrymen, the Scots of Britain and Ireland, as much as by his Pictish converts, and in his character of chief ecclesiastical ruler he gave formal benediction and inauguration to Aidan, the successor of Conall, as king of the Scots.
On the father's side he was descended from the Conall Gabhrain of the old Dalriadic Scottish kingdom, and the claims of father and son to the Pictish throne were probably through female descent.
Like the family of O'Neill, that of O'Donnell was descended from Niall of the Nine Hostages, king of Ireland at the beginning of the 5th century; the O'Neills, or Cinel l Owen, tracing their pedigree to Owen (Eoghan), and the O'Donnells, or Cinel Connell, to Conall Gulban, both sons of Niall.
606), king of the Scottish kingdom of Dalriada, was the son of Gabran, king of Dalriada, and became king after the death of his kinsman King Conall, when he was crowned at Iona by St Columba.
The north of Ulster is stated to have been conquered and colonized by Conall and Eogan, sons of Niall Noigiallach.
Four of his sons, Loigaire, Conall Crimthand, Fiacc and Maine, settled in Meath and adjoining territories, and their posterity were called the southern Hy Neill.
The other four, Eogan, Enna Find, Cairpre and Conall Gulban, occupied the northern part of Ulster.
The descendants of Eogan were the O'Neills and their numerous kindred septs; the posterity of Conall Gulban were the O'Donnells and their kindred septs.