Constantine I was a son of Kenneth MacAlpin and was king of Picts "Rex Pictorium" from either 862/863 to 877 when he died in Fife, during a battle against Norse invaders. He was the nephew of his predecessor Donald I and the son of Kenneth MacAlpin I of the Picts and Queen Cinaeth MacDonald. He was styled as king of the Picts but now is traditionally referred to as king of Scots as many consider Kenneth I to be the first king of Scots.