The Battle of Saint-Omer, fought on 26 July 1340, was a major engagement in the early stages of the Hundred Years' War, during Edward III's 1340 summer campaign against France launched from Flanders. The campaign was initiated in the aftermath of the English naval victory at the Battle of Sluys but was far less successful than Edward had hoped. At Saint-Omer, the heavily-outnumbered French men-at-arms, tasked with defending the city and awaiting reinforcements, unexpectedly defeated the Anglo-Flemish forces on their own. The allies suffered heavy losses and the French captured their camp intact, taking many warhorses, draft animals and carts, all the tents, huge quantities of supplies and most of the Flemish standards. Edward's campaign of 1340 had begun badly. On the bright side, the loss of several thousand men was bearable, as the survivors, which included most of the precious English longbowmen, eventually rejoined him at Tournai. The defeat had serious strategic consequences. It exposed southern Flanders to the wrath of Philip VI and enabled the French to concentrate their forces against the main army of the coalition in the siege of Tournai.