Of French offensive action against the overwhelming forces of their enemies there could be no question. Villars, who commanded the armies of Louis XIV. upon the north-eastern frontier, opposing Marlborough and Eugene, drew up a line of defence consisting of entrenchments, flooded land, and the use of existing watercourses, a line running from the neighbourhood of Douai away eastward to the Belgian frontier. Behind this line, with his headquarters at La Bassée,[1] he waited the fatal assault.
It was at the close of June that the enemy's great forces moved. Their first action was not an attempt to penetrate the line but to take the fortresses upon its right, which taken, the defence might be turned. They therefore laid siege to Tournai, the first of the two fortresses guarding the right of the French line. (Mons was the second.)
Here the first material point in the campaign showed the power of resistance that tradition and discipline yet maintained in the French army. The long resistance of Tournai and its small garrison largely determined what was to follow. Its siege had been undertaken in the hope of its rapid termination, which the exiguity of its garrison and the impossibility of its succour rendered probable. But though Marlborough had established his headquarters before the place by the evening of the 27th of June, and Eugene upon the next day, the 28th, though trenches were opened in the first week of July and the first of the heavy fighting began upon the 8th of that month, though the town itself was occupied after a fortnight's struggle, yet it was not until the 3rd of September that the citadel surrendered.
This protracted resistance largely determined what was to follow. While it lasted no action could be undertaken against Villars. Meanwhile the French forces were growing stronger, and, most important of all, the first results of the harvest began to be felt.
Tournai once taken, it was the business of the allies to pierce the French line of defence as soon as possible, and with that object to bring Villars to battle and to defeat him.
The plan chosen for this object was as follows:--
The allied army to march to the extreme right of the positions which the French could hope to defend. There the allies would contain the little garrison of Mons. Thither the mass of the French forces must march in order to bar the enemy's advance upon Paris, and upon some point near Mons the whole weight of the allies could fall upon them, destroy them, and leave the way to the capital open.