Dictionary of National Biography, 1885-1900/Aidan (d.606)
AIDAN (d. 606), king of the Scottish kingdom of Dalraida, was the son of Gabran, a former king of Scottish Dalraida, which was originally formed of a portion of the west coast of Scotland by Fergus Mor, son of Erc, who came at the end of the fifth century from Irish Dalraida. According to the law of tanistry which governed the succession, Gabran was immediately succeeded by a relative named Conall, and it was only after Conall's death that the throne was accessible to Aidan. It was St. Columba who chose him to be king in preference to his brother Eaganan, and solemnly crowned him in the island of Iona. Aidan pursued a vigorous policy. The Dalraid Scots were, before his time, regarded as an Irish colony and subject to the mother tribe in Ireland. In 575 Aidan attended a great council at Drumceat, and announced to the Irish his intention to govern Scottish Dalraida as an independent kingdom. In 603 he led a large force of Britons and Scots against Ethelfrith, the Anglian king of Bernicia, and was defeated at a spot called by Bede ‘Degsastan,’ which is probably in Liddesdale. Bede notes that so signal was the defeat inflicted on Aidan, that no like attempt had since been made up to his own time (731) in northern England. Aidan died in 606, and St. Columba named his son Eocha Buidhe, or ‘the yellow-haired,’ his successor.
[Skene's Celtic Scotland, i. 143, 162–3, 229, 239, 247, 249; Bede's Hist. Ecclesiast. lib. i. c. xxxiv.; Reeves's Adamnan, pp. 81, 264; Biog. Brit., where a long account is given of the mythical history of Aidan as related by Hector Boece and later writers; Pinkerton's Enquiry into Scottish History, ii. 114.]