Why Henry was in France
In 1415 the English king Henry V crossed the Channel to pursue claims in France that went back to the Hundred Years War: the English crown’s old rights in parts of the country, and the larger claim to the French throne that Edward III had put forward decades earlier. France was also divided at the time by a bitter rivalry among its great nobles, which Henry hoped to exploit.
He landed in northern France in August and besieged the port of Harfleur. The town held out longer than he had expected, and by the time it surrendered in September the campaigning season was well advanced. Disease also hit his army, and many men died or were sent home sick. Instead of staying put, Henry chose to march his remaining troops overland toward Calais, an English-held town, in what was effectively a show of strength. The Agincourt campaign thus began as a siege, not as a plan for a great battle.
A march that went wrong
The march was hard. The English found river crossings broken or guarded, and had to turn upstream to find a way over. A larger French army, assembled under leading nobles, shadowed them and eventually blocked the road. Henry’s men were tired, hungry and wet, and probably outnumbered by a considerable margin. Modern estimates of the sizes vary widely. A common view is that the English had several thousand men, most of them archers, and the French had a substantially larger force, but no precise figure is certain.
The field
The armies met on 25 October 1415 near the village of Azincourt, which the English spelled Agincourt. The ground lay between two patches of woodland, which narrowed the front. Heavy rain had fallen, and the field was recently plowed, so it was soft and muddy.
Henry’s archers were placed on the flanks, and, according to accounts, they drove sharpened stakes into the ground in front of them as protection against cavalry. The English men-at-arms stood in the center on foot. The French, who relied on armored knights, planned to break the English with a mounted charge and a heavy dismounted advance.
The longbow and the mud
The longbow is the best-known part of the story. A trained archer could shoot many arrows a minute, and the arrows landing in great numbers troubled horses and men alike. Plate armor gave good protection against many hits, so historians debate how many knights were killed by arrows alone and how many were hurt in other ways. The arrows may have mattered more by forcing the French to lower their heads, narrowing their vision, and by disrupting the horses.
The mounted charge failed. Horses panicked or were hurt, and some riders fell back on the advancing lines. The main French body then had to cross the soft ground on foot, in heavy armor. Many accounts describe it as exhausting, and the crowding between the woods meant men could not easily use their weapons. When they closed with the English, the archers, who also carried swords and axes, joined the fight in the melee.
At one point Henry ordered that prisoners be killed, apparently fearing an attack from the rear while the English were still outnumbered. Chroniclers disagree on the details, and the episode has long been argued about as a matter of military necessity versus a breach of the knightly customs of the time.
Losses
The French suffered extremely heavy losses among their nobility, with several leading lords killed or captured. English losses were far lower, though sources differ on the numbers and the figures should be treated cautiously.
How much of a turning point?
Agincourt was a spectacular victory, and it left English prestige very high. It also removed many French leaders and added to the political splits in France. Henry went on to conquer Normandy in the following years, and in 1420 the Treaty of Troyes named him as heir to the French king. Historians still debate how much these gains rested on the battle itself and how much on French divisions.
But the result was not permanent. Henry died in 1422, leaving an infant son, and the French recovered over the following decades. Agincourt remains important as a victory by a smaller force and as a cultural landmark, though the long war, which the Black Prince victories and later Joan of Arc had each shaped in different phases, was not decided on that single day. Earlier fights such as the Battle of Crecy and the Battle of Poitiers form part of the same pattern in which English archers repeatedly achieved victories against larger armies.