From 1412 he was constantly employed on diplomatic missions. In 1413 he was one of the ambassadors to treat for a marriage between Henry, Prince of Wales, and Anne, daughter of John, Duke of Burgundy. Next year he was one of those appointed to procure a prolongation of the truce with France, and one of the ambassadors to negotiate a marriage between Henry V and Catherine of France. In August 1415 he was employed to negotiate a truce with Robert Stewart, Duke of Albany, regent of Scotland, and shortly after was made Warden of the Eastern Marches. In 1418 he was Governor of the Castle of Argentan in Normandy.
