David I of Scotland

David I (c. 1084–1153), youngest son of Malcolm III and Saint Margaret, entered the court of Henry I as a young man before succeeding his brother Alexander I as king of Scots in 1124. He spent a decade subduing rivals such as Óengus of Moray.

Backing his niece Matilda against Stephen, he invaded England, was defeated at the Battle of the Standard in 1138, yet secured Northumberland and Cumbria. His reign brought the Davidian Revolution of burghs, monasteries and feudal tenure. He died at Carlisle in 1153, venerated as a saint.