Dictionary of National Biography, 1885-1900/Culen
CULEN or COLIN, son of Indulph, king of Scotland or Alba (967–71?), was an unimportant king of the united Scotch Pictish monarchy, whose capital was Scone. His father, Indulph, was the first king who occupied Edinburgh, up to that time within Anglian Northumbria. On the death of Indulph in a conflict with the Norwegians at Invercaliss, according to the later chroniclers, or, as Mr. Skene conjectures, Indulph having, like his father Constantine, resigned the crown and become a monk (Celtic Scotland, i. 366), Dubh, the son of Malcolm, succeeded by the law of tanistry, but his succession was disputed by Culen. In 965 Culen was defeated at Duncrub in Strathearn by Dubh, with the aid of the lay abbot of Dunkeld and the governor of Athol. But two years later Dubh was defeated and slain, perhaps at Kinloss, near Forres, and Culen acquired his father's throne. The only event recorded in his uneventful reign is the close of it by his death, along with his brother Eocha, at the hands of the Britons, which is placed both by the ‘Pictish Chronicle’ and the ‘Annals of Ulster’ in 971.
[Robertson's Scotland under her Early Kings; Skene's Celtic Scotland.]