Marlborough had watched, with the deepest anxiety, the progress of the French arms on the Rhine and in Bavaria, and he saw the futility of carrying on a war of posts and sieges in Flanders, while death-blows to the empire were being dealt on the Danube. He resolved therefore to let the war in Flanders languish for a year, while he moved with all the disposable forces that he could collect to the central scenes of decisive operations. Such a march was in itself difficult, but Marlborough had, in the first instance, to overcome the still greater difficulty of obtaining the consent and cheerful co-operation of the Allies, especially of the Dutch, whose frontier it was proposed thus to deprive of the larger part of the force which had hitherto been its protection. Fortunately, among the many slothful, the many foolish, the many timid, and the not few treacherous rulers, statesmen, and generals of different nations with whom he had to deal, there were two men, eminent both in ability and integrity, who entered fully into Marlborough's projects, and who, from the stations which they occupied, were enabled materially to forward them. One of these was the Dutch statesman Heinsius, who had been the cordial supporter of King William, and who now, with equal zeal and good faith, supported Marlborough in the councils of the Allies; the other was the celebrated general Prince Eugene, whom the Austrian cabinet had recalled from the Italian frontier, to take the command of one of the Emperor's armies in Germany. To these two great men, and a few more, Marlborough communicated his plan freely and unreservedly; but to the general councils of his allies he only disclosed part, of his daring scheme. He proposed to the Dutch that he should march from Flanders to the Upper Rhine and Moselle, with the British troops and part of the Foreign auxiliaries, and commence vigorous operations against the French armies in that quarter, whilst General Auverquerque, with the Dutch and the remainder of the auxiliaries, maintained a defensive war in the Netherlands. Having with difficulty obtained the consent of the Dutch to this portion of his project, he exercised the same diplomatic zeal, with the same success, in urging the King of Prussia, and other princes of the empire, to increase the number of the troops which they supplied, and to post them in places convenient for his own intended movements.
Marlborough commenced his celebrated march on the 19th of May. The army, which he was to lead, had been assembled by his brother, General Churchill, at Bedburg, not far from Maestricht on the Meuse: it included sixteen thousand English troops, and consisted of fifty-one battalions of foot, and ninety-two squadrons of horse. Marlborough was to collect and join with him on his march the troops of Prussia, Luneburg, and Hesse, quartered on the Rhine, and eleven Dutch battalions that were stationed at Rothweil. [Coxe's Life of Marlborough.] He had only marched a single day, when the series of interruptions, complaints, and requisitions from the other leaders of the Allies began, to which he seemed doomed throughout his enterprise, and which would have caused its failure in the hands of any one not gifted with the firmness and the exquisite temper of Marlborough. One specimen of these annoyances and of Marlborough's mode of dealing with them may suffice. On his encamping at Kupen, on the 20th, he received an express from Auverquerque pressing him to halt, because Villeroy, who commanded the French army in Flanders, had quitted the lines, which he had been occupying, and crossed the Meuse at Namur with thirty-six battalions and forty- five squadrons, and was threatening the town of Huys. At the same time Marlborough received letters from the Margrave of Baden and Count Wratislaw, who commanded the Imperialist forces at Stollhoffen near the left bank of the Rhine, stating that Tallard had made a movement, as if intending to cross the Rhine, and urging him to hasten his march towards the lines of Stollhoffen. Marlborough was not diverted by these applications from the prosecution of his grand design. Conscious that the army of Villeroy would be too much reduced to undertake offensive operations, by the detachments which had already been made towards the Rhine, and those which must follow his own march, he halted only a day to quiet the alarms of Auverquerque. To satisfy also the margrave he ordered the troops of Hompesch and Bulow to draw towards Philipsburg, though with private injunctions not to proceed beyond a certain distance. He even exacted a promise to the same effect from Count Wratislaw, who at this juncture arrived at the camp to attend him during the whole campaign. [Coxe.]
Marlborough reached the Rhine at Coblentz, where he crossed that river, and then marched along its right bank to Broubach and Mentz. His march, though rapid, was admirably conducted, so as to save the troops from all unnecessary fatigue; ample supplies of provisions were ready, and the most perfect discipline was maintained. By degrees Marlborough obtained more reinforcements from the Dutch and the other confederates, and he also was left more at liberty by them to follow his own course. Indeed, before even a blow was struck, his enterprise had paralysed the enemy, and had materially relieved Austria from the pressure of the war. Villeroy, with his detachments from the French-Flemish army, was completely bewildered by Marlborough's movements; and, unable to divine where it was that the English general meant to strike his blow, wasted away the early part of the summer between Flanders and the Moselle without effecting anything. ["Marshal Villeroy," says Voltaire, "who had wished to follow Marlborough on his first marches, suddenly lost sight of him altogether, and only learned where he really was, on hearing of his victory at Donauwert." - SIECLE DE LOUIS XIV.]