A few days before the invasion of France, King Henry uncovered the Southampton Plot and the participation in it of Edward's younger brother, Richard of Conisburgh, Earl of Cambridge, for which the younger brother was beheaded on 5 August 1415. Edward himself was not implicated in the conspiracy, and he departed with the army for France. He was present at the Siege of Harfleur, where he made his will on 17 August 1415, then he commanded the van on the army's march through northern France. He commanded the right wing at the Battle of Agincourt on 25 October 1415, during which he became the highest-ranking English casualty. According to some, he rushed forward to save King Henry V who had been assisting his younger brother, Humphrey of Gloucester, and had been assailed and wounded by the Duke of Alençon. York's intervention saved the King's life but cost the duke his own. His death has been variously attributed to a head wound and to being 'smouldered to death' by 'much heat and pressing'. York was buried in the Church of St Mary and All Saints, Fotheringhay, where he had earlier established a college for a master and twelve chaplains. The monument now in the church was erected during the reign of Queen Elizabeth I.