Secular Hereditary Abbot Of Dunkeld

Slain in 1045 by Macbeth near Dunkeld "with nine times twenty heroes" as he led an aborted attempt to put his grandson, Malcolm, on the throne.
Lord of the Isles & Mormaer of Atholl

Lord and Mormaer of Athole, Abthane of Dule and Hereditary Lay Abbot of Dunkeld (who commanded the left wing of the Scottish army at the battle of Luncarty c990) Crinan's grandfather, also Duncan, was killed (together with his opponent Dubdon, Mormaer of Athole) at the battle of Dundub c965. Although the exact lineage has not been recorded, it is believed that he was of the kin of St. Columba and descended from the Cineal Conaill of the Tyrconnell branch of the descendants of Niall of the Nine hostages.

Re: Duncan, Crinan's son: the House of Dunkeld: "When Malcolm II was murdered by his nobles at Glamis, Duncan killed his opponents and seized the throne as King Duncan I. His first cousins, Macbeth and Thorfinn the Raven Feeder, Norwegian Earl of Orkney, united to advance MacBeth's claim to the throne through his mother, another daughter of Malcolm II. Duncan reigned from 1034 until he was defeated in battle by their combined armies and killed by MacBeth in August 14, 1040 near Elgin.