On 11 November 1216 at Gloucester, upon the death of King John, William Marshal was named by the king's council (the chief barons who had remained loyal to King John in the First Barons' War) to serve as protector of the nine-year-old King Henry III, and regent of the kingdom. In spite of his advanced age (around 70) he prosecuted the war against Prince Louis and the rebel barons with remarkable energy. In the battle of Lincoln he charged and fought at the head of the young King's army, leading them to victory. He was preparing to besiege Louis in London when the war was terminated by the naval victory of Hubert de Burgh in the straits of Dover.