The first Earl went on to fight with King Charles I at the battle of Naseby on 14 June 1645, where the Earl received some blame for the loss of the battle. King Charles, attempting to rally his men, rode forward but as he did so, the Earl seized his bridle and pulled him back, fearing for the King's safety. Lord Carnwath's action was misinterpreted by the royalist soldiers as a signal to move back, leading to a collapse of their position. The military balance then tipped decisively in favour of Parliament.