The Earl of Douglas was trying to consolidate the power which he had gained through the murder of his cousins at the "Black Dinner" at Edinburgh Castle, sanctioned by the king and his own father James the Gross, 7th Earl of Douglas.
The powerful Earl of Douglas sought to solidify his control, having obtained it through the brutal murder of his family members at the infamous "Black Dinner" within Edinburgh Castle, sanctioned by the monarch and his own father, James the Gross, 7th Earl of Douglas.