The Battle of Blanchetaque was fought on 24 August 1346 between an English army under King Edward III and a French force commanded by Godemar du Fay. The battle was part of the Crécy campaign, which took place during the early stages of the Hundred Years' War. After landing in the Cotentin Peninsula on 12 July, the English army had burnt a path of destruction through some of the richest lands in France to within of Paris, sacking a number of towns on the way. The English then marched north, hoping to link up with an allied Flemish army which had invaded from Flanders. They were outmanoeuvred by the French king, Philip VI, who garrisoned all of the bridges and fords over the River Somme and followed the English with his own field army. The area had previously been stripped of food stocks by the French, and the English were essentially trapped.
Hearing of a ford at Blanchetaque, from the sea, Edward marched for it and encountered the blocking force under du Fay. Once the ebbing tide had lowered the water level, a force of English longbowmen marched partway across the ford and, standing in the water, engaged a force of mercenary crossbowmen, whose shooting they were able to suppress. A French cavalry force attempted to push back the longbowmen but were in turn attacked by English men-at-arms. After a mêlée in the river, the French were pushed back, more English troops were fed into the fight, and the French broke and fled. French casualties were reported as over half of their force, while English losses were light. Two days after Blanchetaque, the main French army under Philip was defeated at the Battle of Crécy with heavy loss of life. Edward ended the campaign by laying siege to Calais, which fell after twelve months, securing an English entrepôt into northern France which was held for two hundred years.
Background
Since the Norman Conquest of 1066, English monarchs had held titles and lands within France, the possession of which made them vassals of the kings of France. The status of the English king's French fiefs was a major source of conflict between the two kingdoms throughout the Middle Ages. English holdings in France had varied in size over the centuries, but by 1337 only Gascony in south-western France and Ponthieu in northern France were left. Following a series of disagreements between Philip VI of France () and Edward III of England (), Philip's Great Council in Paris on 24 May 1337 agreed that the Duchy of Aquitaine, effectively Gascony, should be taken back into Philip's hands on the grounds that Edward was in breach of his obligations as a vassal. This marked the start of the Hundred Years' War.
Early in 1345, Edward determined to attack France on three fronts: a small force would sail for Brittany; a slightly larger force would proceed to Gascony under the command of the Henry, Earl of Derby; and the main force would accompany him to either northern France or Flanders. The French anticipated, correctly, that the English planned to make their main effort in northern France. Thus, they directed what resources they had to the north, planning to assemble their main army at Arras on 22 July. South-western France and Brittany were encouraged to rely on their own resources.
The main English army sailed on 29 June 1345 and anchored off Sluys in Flanders. Edward was unexpectedly threatened with the loss of his Flemish allies, and to avoid this was forced to attend to diplomatic affairs. By 22 July, although the Flemish situation was unresolved, men and horses could be confined on board ship no longer and the fleet sailed, probably intending to land in Normandy. It was scattered by a storm, and individual ships found their way over the following week to various English ports where they disembarked. There was a further week's delay while the King and his council debated what to do, by which time it proved impossible to do anything major with the main English army before winter. Aware of this, Philip VI despatched reinforcements to Brittany and Gascony. During 1345, Derby led a whirlwind campaign through Gascony at the head of an Anglo-Gascon army. He heavily defeated two large French armies at the battles of Bergerac and Auberoche, captured French towns and fortifications in much of Périgord and most of Agenais, and gave the English possessions in Gascony strategic depth.