An event soon occurred which showed how wide-spread were the intrigues of the French in the Flemish towns, and how insecure was the foundation on which the authority of the Allies rested there. An accidental circumstance led to the discovery of a letter put into the post-office of Ghent, containing the whole particulars of a plan for admitting the French troops into the citadel of Antwerp. Vendome at the same time made a forward movement to take advantage of these attempts; but Marlborough was on his guard, and both frustrated the intended rising in Antwerp, and barred the way against the attempted advance of the French army. Disconcerted by the failure of this enterprise, Vendome moved to Soignies at the head of an hundred thousand men, where he halted at the distance of three leagues from the Allied armies. A great and decisive action was confidently expected in both armies; as, although Marlborough could not muster above eighty thousand combatants, it was well known he would not decline a battle, although he was not as yet sufficiently strong to assume the offensive. Vendome, however, declined attacking the Allies where they stood, and, filing to the right to Braine la Leude, close to the field of Waterloo, again halted in a position, threatening at once both Louvain and Brussels. Moving parallel to him, but still keeping on the defensive, Marlborough retired to Anderleet. No sooner had he arrived there, than intelligence was received of a farther movement to the right on the part of the French general, which indicated an intention to make Louvain the object of attack. Without losing an instant, Marlborough marched on that very night with the utmost expedition, amidst torrents of rain, to Parc, where he established himself in such strong ground, covering Louvain, that Vendome, finding himself anticipated in his movements, fell back to Braine-le-Leude without firing a shot.[17]