Constantine II of Scotland

Causantín mac Áeda, anglicised Constantine II (died 952), son of Áed and grandson of Kenneth MacAlpin, ruled Alba from 900 to 943, the longest reign of any early Scottish king. He spent it containing the Uí Ímair Vikings and the ambitions of Wessex.

After Æthelstan invaded Alba in 934, he allied with the kings of Dublin and Strathclyde, but was defeated at Brunanburh in 937, where his son Cellach fell. In 943 he abdicated to the Culdee monastery at St Andrews and died there in 952; his reign saw Pictland remade as the Gaelic kingdom of Alba.