In 1449 James II reached adulthood, but he had to struggle to gain control of his kingdom. The Douglases, probably with his cooperation, used his coming of age as a way to throw the Livingstons out of the shared government, as the young king took revenge for the arrest of his mother that had taken place in 1439 and the assassination of his young Douglas cousins in which Livingston was complicit. Douglas and Crichton continued to dominate political power, and the king continued to struggle to throw off their rule. Between 1451 and 1455, he struggled to free himself from the power of the Douglases. Attempts to curb the Douglases' power took place in 1451 during the absence of William Douglas, 8th Earl of Douglas, from Scotland and culminated with the murder of Douglas at Stirling Castle on 22 February 1452.