His first act as Duke of Burgundy was to forge an alliance with Henry V of England, signing the Treaty of Troyes, in which Queen Isabella of France named Henry V as successor to the French throne. Philip was a powerful ally: by the early decades of the 15th century his territories included Namur (acquired 1421), Holland and Zeeland (1428), Brabant (1430), Luxembourg (1435) and the bishoprics of Liège, Cambrai, and Utrecht were under Burgundian control. Some were his by inheritance, others had come through marriage, purchase, or conquest and they combined to constitute a formidable ‘state’. The Treaty of Arras (1435) released Philip from the duty of doing homage to the French king and rendered him virtually independent of royal control. However, the king of France succeeded in breaking the alliance between France and England and from 1435 France and Burgundy joined forces to wage war on England. The imposition of taxes on the Burgundians provoked a rebellion, led by Ghent, but the rebels (of whom 20,000 were killed) were defeated (1454). Philip’s court in Burgundy was the most prosperous and civilized in Europe. He founded an order of chivalry, the Order of the Golden Fleece, and patronized Flemish painters.