With the demise of the Army of the Solemn League and Covenant, Leven retired from active military command. Splits within the Scottish Parliament saw the Royalist Engager party led by James, 3rd Marquis Hamilton oust the Argyll radicals. Leven and his subordinate David Leslie, both declined command of this army. Hamilton led an ill-supported army over the border in support of the king. They were soundly defeated by English parliamentary forces at the Battle of Preston in 1648. This led to the return of the Argyll faction in Scotland after the Whiggamore Raid. After the execution of Charles I, Argyll declared his son, Charles II, King of Great Britain and Ireland leading to the Cromwellian invasion of Scotland. The Covenanters were defeated (1650) at the battle of Dunbar.