The operations upon the Somme in the autumn of 1916 had given the British command of the high ground in the Somme district. The next move was to obtain a similar command in the continuation of the same high ground to the north. This was accomplished from Arras to Lens in the great battle which began upon April 9, 1917. After the complete conquest of this Vimy position, the next step was obviously to attack the prolongation of the same ridge in the Ypres direction. This was carried out with great success upon June 7 in the Battle of Messines, when nine miles of commanding country were carried and permanently held, from the neighbourhood of Ploegstrate in the south to Hill 60 and Mount Sorel in the north. Thus many spots which will for ever be associated with the glorious dead--Hill 60 itself, with its memories of the old 13th and 15th Brigades, Wytschaete, where the dismounted troopers fought {95} so desperately in the fall of 1914; Messines, sacred also to the memory of the cavalry and of the British and Indian infantry who tried hard to hold it; finally the long, gently sloping ridge which was reddened by the blood of the gallant London Scots when they bore up all night amid fire and flame against the ever-increasing pressure of the Bavarians--all these historic places came back once more into British keeping. It is this action, so splendid both in its execution and in its results, which we have now to examine, an action which was a quick sequel to the order of the German command that "the enemy must not get Messines Ridge at any price." For two thankless years Sir Herbert Plumer, the officer who in his younger days had held on in such bulldog fashion to the country north of Mafeking, had been the warden of the Ypres salient. His task had been a peculiarly difficult and responsible one--indeed, many a military critic might have said _a priori_ that it was an impossible one. The general outline of the British trenches formed a loop rather than a salient, and there was no point in it which could not be shot into from behind. Add to this that all the rising ground, and therefore all the observation, lay with the enemy, and that the defending troops were very often skeleton divisions which had come up exhausted from the south. Taking all these circumstances together, one can understand the facts which turned General Plumer's hair white during these two years, but never for an instant weakened the determination of his defence. There was no one in the Army who did not rejoice, therefore, when it was learned that the Second Army had been chosen for the next attack, and that the long-suffering Plumer {96} was at last to have a chance of showing that he could storm a line as well as hold one.