Europe entered an arms race to build ever larger artillery pieces. By the early 15th century both French and English armies were equipped with larger pieces known as bombards, weighing up to 5 tons (4,535 kg) and firing balls weighing up to 300 lbs (136 kg). The artillery trains used by Henry V of England in the 1415 Siege of Harfleur and 1419 Siege of Rouen proved effective in breaching French fortifications, while artillery contributed to the victories of French forces under Joan of Arc in the Loire Campaign (1429).