Battle of Crecy

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 in a devastating defeat for France. Cannons were used for first time in battle in Europe but not effectively. From the article:

"Battle of Crecy
During the Hundred Years War, King Edward III’s English army annihilates a French force under King Philip VI at the Battle of Crecy in Normandy. The battle, which saw an early use of the deadly longbow by the English, is regarded as one of the most decisive in history.

On July 12, 1346, Edward landed an invasion force of about 14,000 men on the coast of Normandy. From there, the English army marched northward, plundering the French countryside. Learning of the Englishmen’s arrival, King Philip rallied an army of 12,000 men, made up of approximately 8,000 mounted knights and 4,000 hired Genoese crossbowmen. At Crecy, Edward halted his army and prepared for the French assault. Late in the afternoon of August 26, Philip’s army attacked.

The Genoese crossbowmen led the assault, but they were soon overwhelmed by Edward’s 10,000 longbowmen, who could reload faster and fire much further. The crossbowmen then retreated and the French mounted knights attempted to penetrate the English infantry lines. In charge after charge, the horses and riders were cut down in the merciless shower of arrows. At nightfall, the French finally withdrew. Nearly a third of their army lay slain on the field, including Philip’s brother, Charles II of Alencon; his allies King John of Bohemia and Louis II of Nevers; and 1,500 other knights and esquires. Philip himself escaped with a wound. English losses were less than a hundred.

The battle marked the decline of the mounted knight in European warfare and the rise of England as a world power. From Crecy, Edward marched on to Calais, which surrendered to him in 1347."