The battle of Clontarf Irish army, commanded overall by Boru, was composed of the division of Munster, the division of Meath, the division of South Connacht, commanded by Maolrunaidh O Heyne, the Scottish division comprising ten Mormaers or Earls of Scotland, including Donald the Earl of Mar, who was killed that day, and one Viking division from Northumbria. Against this army was Mael Morda, King of Leinster, who was in revolt against Boru, the army of the Danes under Sitric Silkbeard, King of Dublin, and the Vikings of Orkney, Man and the Hebrides under the command of Earl Sigurd the fat, earl of Orkney.9