How Did Gunpowder Change Medieval Warfare?

Gunpowder did not, in itself, transform medieval warfare — the longbow, the mounted lance, and the high medieval castle had already done that work. What gunpowder did was to render the old model obsolete in the space of a single century. Cannon ended the strategic dominance of the high castle, dismounted the armoured knight as the decisive battlefield arm, and forced the military-fiscal state into existence. By the end of the Hundred Years’ War the field army of 1337, in which the feudal levy and the mounted man-at-arms were central, had given way to a recognisably early-modern system: contracted infantry, professional cavalry in the French compagnies d’ordonnance, and a standing train of field artillery. Philippe Contamine’s La Guerre de Cent Ans (1968) treats the transformation as the war’s defining legacy.

The slow European arrival

Gunpowder was a Chinese invention of the ninth or tenth century, transmitted westward through the Mongol world. The first securely documented use in European warfare is the Florentine inventory of 1326, followed soon after by traces in English and French royal accounts. The earliest European weapons were not cannon in the modern sense: they were powder charges fixed to arrows or lances, used in the open field. Berthold Schwarz, the legendary German alchemist, is a fourteenth-century attribution and almost certainly fictional. The first true cannon — iron or bronze tubes, powder-charged, firing stone or early iron shot — appear in the 1320s and 1330s, initially as siege weapons and as curiosities of court ceremonial.

Cannon in the Hundred Years’ War

Edward III’s artillery train was a meaningful element of the siege of Calais in 1346–1347, though it was not decisive. The first major use of cannon in the field to influence a battle’s outcome is conventionally placed at the siege of Orléans in 1428–1429, where the English besieging force, under the Earl of Salisbury, was killed on 27 October 1428 by a cannon shot from the town’s defences. The first major English use of cannon in the field was Henry V’s train at the siege of Harfleur, which opened the 1415 campaign and forced the town to surrender on 22 September 1415 after a five-week bombardment. Cannon were expensive, slow-firing, and dangerous to their crews; their principal use, throughout most of the war, was psychological and against static fortifications.

The Bureau brothers and the French train

The decisive development of gunpowder in the war was French. Jean Bureau (c. 1390–1463) and his brother Gaspard (c. 1395–1469), sons of a minor noble family from the Loire, took charge of the French royal artillery in the 1430s and built it into the most powerful in Europe. Jean, who was also Master of the Mint, brought the metallurgical and logistical skills; Gaspard, his field commander, brought the operational ones. The brothers standardised the calibres of the French cannon, professionalised the gun crews, and developed the field-fortification techniques that turned artillery from a siege weapon into a battlefield weapon. The French reconquest of Normandy in 1449, of Gascony in 1451, and of Bordeaux in 1453 was carried by the brothers’ train.

Castillon, 17 July 1453

The conventional test case is the Battle of Castillon, fought on 17 July 1453 on the banks of the Dordogne. The French army, under the constable Arthur de Richemont and with Gaspard Bureau commanding the artillery, had constructed a fortified camp on a rise south of the town, defended by a palisade and a substantial train of field guns. John Talbot, Earl of Shrewsbury, in his late sixties, attacked the camp head-on with perhaps 4,000 men, without scouting, in the conviction that the English longbow and the knight’s charge would prevail as they had at Agincourt thirty-eight years earlier. The cannon destroyed him. Talbot and his son John Talbot, Viscount Lisle, were both killed. Bordeaux surrendered on 19 October 1453. Castillon is the moment when the gun definitively replaced the longbow as the dominant battlefield arm.

The collapse of the high castle

The consequence for fortification was equally sharp. The high medieval castle — tall stone walls, square keeps, deep moats — had been the strategic centrepiece of medieval warfare for three centuries. A determined bombardment could now reduce one in weeks. The response, developed in Italy in the late fifteenth and early sixteenth centuries, was the trace italienne bastion fort: low, thick-walled, angular, designed to deflect cannon shot. The transition took a generation. It was, in Christopher Allmand’s phrase in The Hundred Years’ War: England and France at War c. 1300–c. 1450 (1988), the most important military architectural change between the tenth and the sixteenth centuries.

The death of the mounted charge

The other casualty was the armoured knight. The independent mounted charge, the tactical signature of medieval warfare from Hastings to Crécy, became suicidal once infantry could deploy field guns supported by pike. The full suit of plate armour, which had been made heavier and more articulated across the fourteenth and fifteenth centuries in response to the longbow, was increasingly irrelevant against a ball at close range. The knight did not disappear — he became the armoured cavalryman, a more specialised and more expensive arm — but the social meaning of knighthood shifted. The mounted man-at-arms of 1453 was a professional soldier paid by indenture, not a feudal levy.

The fiscal-military state

None of this was possible without money. The French artillery train was paid for by the permanent taille granted by the Estates-General at Orléans in 1439, by the salt tax (gabelle), and by the now-regular clerical décime. The English response to the French fiscal revolution — the parliamentary taxation of the 1430s and 1440s — was the basis of the English war effort and the training ground for the parliamentary politics of the Wars of the Roses. The military revolution and the fiscal revolution were the same revolution, viewed from two sides.

Legacy

The Hundred Years’ War did not, in 1453, end the medieval period in warfare. But it ended the medieval period in the strict sense. By 1500 the field army looked like a field army of 1600: contracted infantry, drilled cavalry, regular pay, integrated artillery, and a fiscal-bureaucratic state behind it. The long bow, the longbow’s culture, the high castle, the feudal levy, and the chivalric ideal of the mounted warrior all receded into memory. The war, as Clifford Rogers argues in The Oxford Encyclopedia of Medieval Warfare and Military Technology (2010), was both the last of the medieval wars and the first of the early modern ones.