The Hanoverians and Hessians had also grievances, and refused to join in any general plan, or to send their troops to form part of the allied army.

Thus all ideas of a campaign in the south were destroyed; but Marlborough persuaded the Dutch to send 10,000 of the troops in their pay across the Alps to assist Prince Eugene, under the promise that he with the English and Dutch troops would defend Flanders.
So the campaign commenced; and on the 19th of May Marlborough joined his army, which lay encamped on the Dyle, on the French frontier.

On the 22nd a Danish contingent, which had at the last moment been dispatched in answer to an urgent appeal of the duke, arrived; and his army now consisted of 73 battalions and 123 squadrons, in all 60,000 men, with 120 guns.

Marshal Villeroi's force, which lay on the other side of the Dyle, consisted of 74 battalions and 128 squadrons--62,000 men, with 130 guns.

They had also, as at Blenheim, the advantage that the troops were all of one nationality, and accustomed to act together, while Marlborough's army consisted of troops of three nations, at least half of them new to war, and unused to act with each other.
Marlborough opened the campaign by moving towards Tirlemont, with a view of laying siege to Namur, where many of the citizens were anxious to throw off the French yoke.