It must indeed, in justice to Marlborough, be borne in mind, that mere military skill was by no means all that was required of him in this arduous and invidious station. Had it not been for his unrivalled patience and sweetness of temper, and his marvellous ability in discerning the character of those with whom he had to act, his intuitive perception of those who were to be thoroughly trusted, and of those who were to be amused with the mere semblance of respect and confidence, - had not Marlborough possessed and employed, while at the head of the allied armies, all the qualifications of a polished courtier and a great statesman, he never would have led the allied armies to the Danube. The Confederacy would not have held together for a single year. His great political adversary, Bolingbroke, does him ample justice here. Bolingbroke, after referring to the loss which King William's death seemed to inflict on the cause of the Allies, observes that, "By his death the Duke of Marlborough was raised to the head of the army, and, indeed, of the Confederacy; where he, a new, a private man, a subject, acquired by merit and by management, a more deciding influence, than high birth, confirmed authority, and even the crown of Great Britain, had given to King William. Not only all the parts of that vast machine, the Grand Alliance, were kept more compact and entire; but a more rapid and vigorous motion was given to the whole; and instead of languishing and disastrous campaigns, we saw every scene of the war full of action. All those wherein he appeared and many of those wherein he was not then an actor, but abettor, however, of their action, were crowned with the most triumphant success.
"I take with pleasure this opportunity of doing justice to that great man, whose faults I knew, whose virtues I admired; and whose memory, as the greatest general and as the greatest minister that our country, or perhaps any other, has produced, I honour." [Bolingbroke, vol. ii. p. 445.]
War, was formally declared by the allies against France on the 4th of May, 1702. The principal scenes of its operation were, at first, Flanders, the Upper Rhine, and North Italy. Marlborough headed the allied troops in Flanders during the first two years of the war, and took some towns from the enemy, but nothing decisive occurred. Nor did any actions of importance take place during this period, between the rival armies in Italy. But in the centre of that line from north to south, from the mouth of the Scheldt to the mouth of the Po, along which the war was carried on, the generals of Louis XIV. acquired advantages in 1703, which threatened one chief member of the Grand Alliance with utter destruction. France had obtained the important assistance of Bavaria, as her confederate in the war. The Elector of this powerful German state made himself master of the strong fortress of Ulm, and opened a communication with the French armies on the Upper Rhine. By this junction, the troops of Louis were enabled to assail the Emperor in the very heart of Germany. In the autumn of the year 1703, the combined armies of the Elector and French king completely defeated the Imperialists in Bavaria; and in the following winter they made themselves masters of the important cities of Augsburg and Passau. Meanwhile the French army of the Upper Rhine and Moselle had beaten the allied armies opposed to them, and taken Treves and Landau. At the same time the discontents in Hungary with Austria again broke out into open insurrection, so as to distract the attention, and complete the terror of the Emperor and his council at Vienna.
Louis XIV. ordered the next campaign to be commenced by his troops on a scale of grandeur and with a boldness of enterprise, such as even Napoleon's military schemes have seldom equalled. On the extreme left of the line of the war, in the Netherlands, the French armies were to act only on the defensive. The fortresses in the hands of the French there, were so many and so strong that no serious impression seemed likely to be made by the Allies on the French frontier in that quarter during one campaign; and that one campaign was to give France such triumphs elsewhere as would (it was hoped) determine the war. Large detachments were, therefore, to be made from the French force in Flanders, and they were to be led by Marshal Villeroy to the Moselle and Upper Rhine. The French army already in the neighbourhood of those rivers was to march under Marshal Tallard through the Black Forest, and join the Elector of Bavaria and the French troops that were already with the Elector under Marshal Marsin. Meanwhile the French army of Italy was to advance through the Tyrol into Austria, and the whole forces were to combine between the Danube and the Inn. A strong body of troops was to be despatched into Hungary, to assist and organize the insurgents in that kingdom; and the French grand army of the Danube was then, in collected and irresistible might, to march upon Vienna, and dictate terms of peace to the Emperor. High military genius was shown in the formation of this plan, but it was met and baffled by a genius higher still.