Dictionary of National Biography, 1885-1900/Congallus III
CONGALLUS III, CONALL CRANDONNA, son of Eocha Buidhe, king of Scottish Dalriada (642–660), succeeded as king of Dalriada on the death of his brother, Donald Brec, who was killed in a battle on the Carron by Owen, a British king (d. 642?), and reigned till 660 (Tighernach), during part of the time in conjunction with another king, Donald, who is supposed to have belonged to another race and not to have been descended from Aidan. This is a period of great darkness in the annals of Dalriada, and Mr. Skene's explanation may be given as the best conjecture of the cause: 'During the remainder of this century we find no descendant of Aidan recorded bearing the title of king of Dalriada; and it is probable from Adamnan's remark, that "from that day, i.e. the death of Donald Brec, to this they have been trodden down by strangers," that the Britons now exercised a rule over them' (Celtic Scotland, i. 250).
[Robertson and Skene.]