King Constantine III (a.k.a. Causantín mac Cuilén) lived from 971 to 997 and was King of Alba from 995 to 997. The wider picture in Scotland at the time is set out in our Historical Timeline.
Constantine was the son of King Culen, and the third cousin of his successor, King Kenneth II. He succeeded to the throne on the murder of King Kenneth II in Fettercairn.
Constantine III was King of Alba for just two years. He is thought to have married, but was childless at the time of his death, bringing to an end his particular branch of the Alpin Dynasty, which had provided five Kings of Alba going back to King Aed's succession 876.
His reign came to an end when, like so many of his predecessors, he met a violent death. Constantine was killed at Rathinveramon, which is thought to be modern day Cramond, just west of Edinburgh. He was buried in the graveyard at Saint Oran's Chapel on the Isle of Iona, and was succeeded by Kenneth III, the nephew of Constantine's predecessor, Kenneth II.