Constantine of Dalriada, also known as Constantine mac Fergus. Constantine was king of Dalriada. He deposed Conall mac Tagd and reigned from 789-820. He is credited to have founded Drunkeld.
He is thought to be the king commemorated on Dupplin Cross, and is a forbearer of Macbeth, the famous Scottish king.
He was also a brother of Ķengus II, who ruled the Picts from 820 to 834, and of Uen, who ruled in 837.
Additionally, he is the father of Drest, joint ruler of the Picts from 834 to 837.
Flavius Valerius Constantinus, the future emperor Constantine, was born at Naissus in the province of Moesia Superior, the modern Nish in Serbia, on 27 February of 271, 272, or 273.
Constantine convened a synod of bishops to hear the complaint; the synod met in Rome's Lateran Council and is known as the Synod of Rome.
"Constantine's Epistle to the Bishops at the Council of Arles: A Defense of Imperial Authorship." JRH 17 (1993) 274-89.
Constantine, having overcome Conal, the son of Tarla, in 789, succeeded him in the throne.
This event, no doubt, hastened the downfall of the Pictish monarchy; and as the Picts were unable to resist the arms of Kenneth, the Scottish king, he carried into execution, in the year 843, a project he had long entertained, of uniting the Scots and Picts, and placing both crowns on his head.
The Picts were recognised as a distict people even in the tenth century, but before the twelfth they lost their characteristic nominal distinction by being amalgamated with the Scots, their conquerors.