All the fortresses on the Scheldt were in the hands of the French, except Oudenarde,[19] which you will find on the accompanying map, thirty miles to the east of Ypres. At the time when our story opens, Oudenarde was about to be attacked by the French. Marlborough made a wonderful forced march, and fell upon them as they were advancing towards the fortress. By nightfall on July 11, 1708, he had won a great victory, and the remnants of the French army had fallen back in disorder to Ghent. While Marlborough was waiting for reinforcements to come up, some of his troops seized a French position near Ypres, and his main army encamped near Menin. Marlborough now proposed to besiege Lille, the greatest fortress on the road to Paris. He could not bring his siege train by way of the river, so it had to lumber slowly along the roads, and while doing so was in great danger of being captured by the enemy. Thanks, however, to his skilful arrangements, his heavy guns arrived safely, and then the siege began in real earnest. Lille was very strongly fortified, and was garrisoned by 15,000 men. While the siege was in progress a French army of more than 100,000 men marched to its succour; but so strongly was Marlborough posted that it did not dare to attack him. Instead of doing so it fell back behind the Scheldt, so as to cut off Marlborough's forces from Brussels. As, however, he still held Ostend, he was able to get supplies from England. The French now tried to seize Ostend, so that Marlborough might be cut off from the sea and bottled up. He sent forces against them; but the French fell back before him and opened the sluices of the canals, thus flooding much of the country between him and the sea. A little later they succeeded in capturing Nieuport, and Marlborough was cut off from Ostend. On 9th December Lille surrendered after the garrison had lost 8,000 men, and the besiegers not less than 14,000. Marlborough also captured Ghent, and at the end of December 1708 the French left Flanders altogether, and retired into their own territory. Thus the valleys of the Lys and Scheldt were recovered. [Illustration: Map illustrating Marlborough's Campaigns in Artois and West Flanders.] Before I proceed with the story of Marlborough's campaigns, let me point out that during the race to the sea there was a similar struggle between the Allies and the Germans for the possession of the same valleys. The Allies were hastening north in order to push across the Lys and Scheldt and cut the German communications. Unhappily the Germans moved northwards so rapidly that this was impossible. Further, when Antwerp fell, a German army was released which made a great effort to outflank the Allies by way of the coast. Each side foiled the other, and the result was the long trench war which will be described in future pages.