The Division moved up at the end of July in huge brigade convoys of 'buses and lorries, and by the 30th was in the back area of the XIX. Corps, between Watou and Poperinghe. Headquarters were established temporarily in the latter town at two houses in the rue d'Ypres. The following morning began the terrible struggle which is generally known as the third Battle of Ypres.[37] The great attack launched that morning was the second stroke of a campaign which had begun triumphantly at Messines. The plans made for 1917 by the Allied Command had been thrown into some confusion by the retirement of the German armies on the Somme to their Hindenburg system, in March, and later by the stopping of General Nivelle's great offensive in Champagne.[38] The British had certainly played their part at Arras and Messines. The British Command could obviously now not count upon another great French offensive for some little while, and it was under the vital necessity of keeping the German armies heavily engaged. Its greater object was to strike at the Belgian coast, where the submarine bases of Ostend and Zeebrugge were becoming a menace so serious to the very existence of the nation. That scheme has not been made public, and its details can be no more than a matter of surmise to any but those in the confidence of the British Command, or the Imperial General Staff. It will not be discussed here. It is known, however, pretty generally, that it involved an attack upon the coast-line and a landing. Camps had been formed near Dunkirk, surrounded by barbed wire, where divisions were to be assembled in greatest secrecy. And as for the attack in the Salient, a glance at a railway map will show how serious an advance across the Passchendaele Ridge upon Roulers would have been to the German communications. A threat to the next great railway, the main Brussels line between Ghent and Bruges, would probably have led to the abandonment of the coast by the enemy. Ludendorff, in mid-July, while the 36th Division was enjoying its repose in peaceful country, had made one move in the game--no more than the move of a pawn in such a struggle, but a clever and effective one. At Lombartzyde, outside Nieuport, he had launched an attack against our troops upon the little slice of ground held by them north of the Yser Canal, driving them back into the river. Two divisions had very serious losses, including over a thousand prisoners, and, worst of all, the "jumping-off" ground for an attack on the coast line had been snatched away.