On June 14, the Germans were forced to abandon an important part of their first-line trenches between the Lys and St. Yvon. On the same day a considerable advance was made east of Ploegsteert Wood, and in the immediate neighbourhood of Gapaard Village. During the night of the 14th a double attack was made: one to the east of Messines; the other along both banks of the Ypres-Comines Canal, to the north-west of Hollebeke. These attacks gave the British a large number of trenches, which they held in spite of fierce counter-attacks. To sum up, during the latter half of June an advance of 500 to 1,000 yards in depth was made along the whole front line between Klein Zillebeke and the Lys. The month of July passed in raids, patrols, and reconnoitring, preparatory to the new offensive of July 31. This far-reaching offensive, which lasted from July 31 to the end of October, may be divided into six successive phases, and ended with the liberation of Ypres. =First Phase= (July 31--August 15.) =Capture of the First and Second German Lines= When the battle began, the firing line extended from Dixmude, along the Yser Canal, then followed the Yperlée River, on the left bank of the Yser Canal. It next passed through Lizerne to Het Sas, whence it followed the canal to Boesinghe. Opposite this village the line crossed the canal and the Ypres-Bruges railway, then passed the Quatre-Chemins cross-roads, descending thence to Essenfarm and Kruppfarm, which lie on either side of the Pilkem Road. Continuing west of Wieltje Village, it passed south of Verlorenhoek Château, skirted Verlorenhoek Village, and descended west of Hooge, after crossing the Ypres-Roulers railway. It next skirted the northern part of Sanctuaire Wood, then entered the latter, coming out to the south of Zwateleen. From there, the line extended southwards, passing west of Hollebeke, east of Gapaard, and skirting the eastern fringe of Ploegsteert Wood. During the fortnight preceding the offensive, changes were made in the order of the forces holding the line. British troops relieved the Belgians and French who had been operating near the coast, in the direction of Lombaertzyde. Moreover, the French forces, placed at the disposal of General Anthoine, had taken up positions between the Belgians and the British from Reninghe to Elverdinghe. [Illustration: FIRST STAGE OF THE ALLIES' ADVANCE FROM JULY 31 TO AUGUST 11, 1917 (31/7--11/8)] At 4 a.m. on July 31, in spite of unfavourable weather, the British troops, under the command of Generals Plumer and Gough, co-operating with the Franco-Belgian troops led by General Anthoine, attacked in force along a front of fourteen miles from Dixmude to the Lys.