The following year, with a considerable body of troops to support his presumed rights, he crossed to the Continent, and passed the winter at Antwerp among the Flemings who had taken up his cause, and with whom, as well as with the Emperor-King of Germany, he effected aggressive alliances. He made a formal declaration of war in 1339, beginning hostilities which were prolonged into the Hundred Years' War, and which as a contest of the English kings for the sovereignty of France produced a series of important revolutions in the fortunes of that country. The first serious action of the war was a naval battle at Sluys, near the Belgian frontier just northeast of Bruges, June 23, 1340. King Edward and his entire navy sailed from the Thames June 22, and made straight for Sluys. Sir Hugh Quiriel and other French officers, with over one hundred and twenty large vessels, were lying near Sluys for the purpose of disputing the English King's passage. Froissart, with his usual terseness, has graphically recorded the combat which ensued. A more important victory was that won in the land battle at Crecy in 1346, which, however, simply paved the way to the capture of Calais, for it was not until the battle of Poitiers, ten years later, that Edward made any progress toward the conquest of France. In 1346, after landing with a force of troops at Cape La Hogue, Edward reduced Cherbourg, Carentan, and Caen, and, with the intention of crossing the Seine at Rouen, commenced his march on Calais, where he was to be joined by his Flemish allies. Philip, making a rapid march from Paris to Amiens, had posted detachments of soldiers along the right bank of the river Somme, guarding every ford, breaking down every bridge, and gradually shutting up the invaders in the narrow space between the Somme and the sea. Edward sent out his marshals with their battalions to find a passage, but they were unsuccessful, until a peasant led them to the tidal ford of Blanchetaque. Although desperately opposed by fully twelve thousand French, under the Norman baron Sir Godemar du Fay, they effected a crossing, and, marching on, encamped in the fields near Crecy. The King of France with the main body of his troops had taken up his quarters in Abbeville. BATTLE OF SLUYS When the King's fleet was almost got to Sluys, they saw so many masts standing before it that they looked like a wood. The King asked the commander of his ship what they could be, who answered that he imagined they must be that armament of Normans which the King of France kept at sea and which had so frequently done him much damage, had burned his good town of Southampton, and taken his large ship the Christopher. The King replied: "I have for a long time wished to meet with them, and now, please God and St. George, we will fight them; for, in truth, they have done me so much mischief that I will be revenged on them if it be possible."