In 1406, with the death of the king, the 4th Earl of Douglas became one of the council of regents to rule Scotland during the childhood of James I of Scotland. In 1412, the 4th Earl had visited Paris, when he entered into a personal alliance with John the Fearless, Duke of Burgundy, and in 1423, he commanded a contingent of 10,000 Scots sent to the aid of Charles VII of France against the English. He was made lieutenant-general in Joan of Arc's French army, and received the title Duke of Touraine, with remainder to his heirs-male, on 19 April 1424. The newly created French duke was defeated and slain at Battle of Verneuil on 17 August 1424, along with his second son, James, and son-in-law John Stewart, 2nd Earl of Buchan.