In consequence of these treasonable proceedings Henry VII seized Edmund's brother William, with four other Yorkist noblemen. Two of them, Sir James Tyrrell and Sir John Wyndham, were executed; William de la Pole was imprisoned; and Edmund de la Pole, 3rd Duke of Suffolk, was outlawed. Then in July 1502 Henry VII concluded a treaty with Maximilian by which the Emperor bound himself not to countenance English rebels. Presently Suffolk fell into the hands of Philip I of Castile, who imprisoned him at Namur and in 1506 surrendered him to Henry VII, on condition that his life was spared. He remained a prisoner until 1513, when he was beheaded by Henry VIII at the time his brother Richard took up arms with the French king.