In 1173 William the Lion of Scotland invaded the North East to claim the earldom of Northumberland. The head of the Umfraville family, Odinel II, refused to support him and as a result the Scottish army tried to take Prudhoe Castle. The attempt failed as the Scots were not prepared to undertake a lengthy siege. The following year William attacked the castle again but found that Odinel had strengthened the garrison, and after a siege of just three days the Scottish army left. Following the siege, Odinel further improved the defences of the castle by adding a stone keep and a great hall.