The Irish king of Dal Riata in Scotland from about 574 to 606, Aedan mac Gabrain was a member of Cenel nGabrain and son of a previous king, Gabran mac Domangairt. While many aspects of his reign are disputed (partly because the two main sources, Adomnan’s "Life of St. Columba" and the Irish chronicles, often provide contradictory evidence), it is clear that Aedan was involved significantly in the politics of both Ireland and Britain.
There are no certain examples of Aedan being engaged in military activity in Ireland, but he was involved in Irish politics. With Columba active in Dal Riata at Iona and elsewhere during his reign, Aedan was involved with the saint’s Cenel Conaill relatives in Ireland, meeting Aed mac Ainmirech, ruler of Cenel Conaill and the northern Ui Neill, at Druim Cett, although it is disputed whether the Irish chronicle date of 575 for this event or a date between 586 and 597 is correct. While the outcome of the meeting is unclear, it is likely that the political relationship between the Ui Neill and Dal Riata was discussed. In Adomnan’s "Life of St. Columba," Columba (Colum Cille) ordains (reluctantly) Aedan as king, the first instance of this practice in Gaelic literature. An earlier version of this tale by Cummene of Iona makes it explicit that Aedan and his successors should be on friendly terms with Cenel Conaill (and perhaps by implication enemies of the Cruthni and Ulaid), which was possibly a reflection of a treaty made between Aedan and Aed mac Ainmirech at Druim Cett, but also a retrospective explanation of the tribulations of Aedan’s descendants after fighting Cenel Conaill in 637.
The Irish chronicles portray Aedan as militarily active in Britain, undertaking an expedition to the Orkneys in 580-581, fighting in either the Isle of Man or near the Firth of Forth in 582-583, and at the battle of Leithreid in 590. He was defeated by the Northumbrians in 600, probably the same event as the battle of Degsastan (dated to 603) described by Bede in his Ecclesiastical History of the English People. Bede states that Aedan attacked in response to Northumbrian encroachment on British territory, which is an indication of Dal Riata interest in the area south of the Clyde-Forth line at this time, an interest halted by this defeat. Adomnan also mentions a battle in Anglo-Saxon territory, perhaps the battle of Degsastan or one in 596, in which Aedan’s son Domangart was killed, and a victorious battle against the Miathi, in lowland Scotland, where two other sons were killed.
In contrast to this checkered picture produced by the earlier sources, Aedan appears in a number of later Irish texts as a powerful ruler, being described as "king of Alba" in the eleventh-century Liber Hymnorum and as a conqueror of the Picts in the "Tripartite Life of Patrick." These depictions probably reflect the reinter-pretation made in the tenth century that the kingship of Alba was the successor of Dal Riata.
