On August 26, 1346, at the Battle of Crécy, south of Calais in northern France, Edward III's English longbows defeated Philip VI's army. Cannons were used for first time in battle. An excerpt from the article:
"Battle of Crécy
The Battle of Crécy on 26 August 1346 CE saw an English army defeat a much larger French force in the first great battle of the Hundred Years' War (1337-1453 CE). Edward III of England (r. 1327-1377 CE) and his son Edward the Black Prince (1330-1376 CE) led their professional army to victory thanks to a good choice of terrain, troop discipline in the heat of battle, use of the devastating weapon the longbow, and the general incompetence of the French leadership under King Philip VI of France (r. 1328-1350 CE). Crécy would be followed up by an even more impressive victory at the Battle of Poitiers in 1356 CE as England got off to a flier in a conflict that would rumble on for 116 years.
The Hundred Years' War
In 1337 CE Edward III of England was intent on expanding his lands in France and he had the perfect excuse as via his mother Isabella of France (b. c. 1289 CE and the daughter of Philip IV of France, r. 1285-1314 CE), he could claim a right to the French throne as nephew of Charles IV of France (r. 1322-1328 CE). Naturally, the current king, Philip VI, was unwilling to step down and so the Hundred Years' War between France and England began. The name of the conflict, derived from its great length, is actually a 19th-century CE label for a war which proceeded intermittently for well over a century, in fact, not finally ending until 1453 CE.
The English longbow was then the most devastating weapon on the medieval battlefield.
The first major action of the wars was in June 1340 CE when Edward III destroyed a French fleet at Sluys in the Low Countries. Next, an army led by the Earl of Derby recaptured Gascony for the English Crown in 1345 CE. Then, to prepare for a field campaign in French territory, Edward III's eldest son, Edward of Woodstock, aka Edward the Black Prince, was charged with torching as many French towns and villages as he could along the Seine Valley through July 1346 CE. This strategy, known as chevauchée, had multiple aims: to strike terror into the locals, provide free food for an invading army, acquire booty and ransom for noble prisoners, and ensure the economic base of one's opponent was severely weakened, making it extremely difficult for them to later put together an army in the field. Inevitably, ordinary troops also took the opportunity to cause general mayhem and loot whatever they could from the raids. This was a brutal form of economic warfare and, perhaps, too, it was designed to provoke King Philip into taking to the field and facing the invading army, which is exactly what happened.
Troops & Weapons
Both sides at Crécy had heavy cavalry of medieval knights and infantry but it would be the English longbow that proved decisive - then the most devastating weapon on the medieval battlefield. These longbows measured some 1.5-1.8 metres (5-6 ft.) in length and were made most commonly from yew and strung with hemp. The arrows, capable of piercing armour, were about 83 cm (33 in) long and made of ash and oak to give them greater weight. A skilled archer could fire arrows at the rate of 15 a minute or one every four seconds. The English army also included a contingent of mounted archers which could pursue a retreating enemy or be deployed quickly where they were most needed on the battlefield.
The French, although they had some archers, relied more on crossbowmen as firing a crossbow required less training to use. The main contingent in Philip's army was composed of Genoese crossbowmen. The crossbow, though, had a seriously slower firing rate than the longbow, about one bolt to five arrows in terms of speed of delivery.
As many as 15 waves of French cavalry attacks were driven back & the English discipline ensured that nobody broke from their defensive formation.
In terms of infantry, the better-equipped men-at-arms wore plate armour or stiffened cloth or leather reinforced with metal strips. Ordinary infantry, usually kept in reserve until the cavalry had clashed, had little armour if any and wielded such weapons as pikes, lances, axes, and modified agricultural tools. Finally, Edward's army did boast some crude cannons - the first to be used on French soil - although their impact would have been limited given the poor technology of the period as they could not, for example, fire downhill."