These elements in the situation, once clearly seized, the sequel follows from them logically enough.
The above describes the situation on the 5th of August.
On the 6th, Wednesday, the united Franco-Bavarian force began its march northward towards the Danube, a march parallel with Marlborough’s line of supply, and threatening that line all the way, ready to cut it when once the northern bank of the Danube was reached. Marlborough was compelled, in view of that march, to go back northward, step for step with his opponents. The artery that fed him was in danger, and everything else must be neglected.
In the evening of that Wednesday, August the 6th, Tallard and the Elector were at Biberach, Marlborough and Baden at Schobenhausen, which, as the map shows, lies also a day’s march to the north from the last position these troops had held, and was on the way to the crossing of the Danube at Neuburg, as the Franco-Bavarians were on the way to the crossing of the same great river at Dillingen.
On the 7th there was no movement, but on the 8th, the Friday, as the Franco-Bavarian host approached the crossing of the Danube at Dillingen, their leader (if Tallard may be regarded as their leader—he was nominally under the orders of the Elector, but he was the marshal of Louis XIV.) heard suddenly that Eugene had appeared at Hochstadt with thirty-nine squadrons and twenty battalions.
The trick was done. The rapid and secret march of Eugene had been accomplished with complete success, and his force was within speaking distance of Marlborough’s.
When the news came to the French camp, it was even there evident what a sudden transformation had come over the campaign; but to one who could see, as the historian sees, the moral condition of both forces, the event is more significant still.
A great commander, whose name was henceforth to be linked most closely with that of Marlborough’s himself, was present upon the Upper Danube. He brought with him troops not only equivalent in number to a third of his colleague’s existing forces, but trained under his high leadership, disciplined in his excellent school, and containing, what will prove essential to the fortunes of the coming battle, a very large proportion of cavalry. Further, the appearance of Eugene at this critical moment permitted Marlborough to rid himself of Louis of Baden, to despatch him to the siege of Ingolstadt in the heart of Bavaria, at once to be free of the clog which the slow decision and slow movements of that general burdened him with, to threaten the heart of the enemy’s country by that general’s departure on such a mission, and to unite himself and his forces with a man whose methods were after his own heart.
It is true that a minor problem lay before Eugene and Marlborough which must be solved before the great value of the junction they were about to effect could be taken advantage of. Their forces were still separated by the Danube: Marlborough lay a day’s march to the south of it, and were he to cross the Danube at Neuburg he would be two days’ march from Eugene. But each army was free to march towards the other, and all that their commanders had to decide was upon which side of the river the junction should be effected. Were the junction effected to the south—that is, were Eugene to cross the Danube and join Marlborough in Bavaria—Tallard, crossing the Danube at Dillingen, could strike at the great northern line of communications which conditioned all these movements. It was, therefore, the obvious move for Eugene and Marlborough to join upon the northern bank of the Danube, and to move upon and defend that all-important line of communications, point for point, as Tallard might threaten it.
It was on the 8th, the Friday, as I have said, that Eugene’s presence was known both to Tallard and to Marlborough, for Eugene had ridden forward and met his colleague.