After the engagement, Coburg pressed the Duke of York to remain with him for yet another fortnight, in order to renew the attack on the French army or to take Cambrai, the last fortress that blocked the way into France. But the Duke could only obey his instructions as to Dunkirk, which had lately been reiterated by Dundas;[145] and the two armies accordingly parted. Coburg, weakened by the withdrawal of nine thousand Prussian troops, and not yet compensated by the restoration of fourteen thousand Austrians from the Rhine, resolved to besiege Quesnoy, and meanwhile spread his force in several detachments from Denain to Bettignies. ◆Aug. 13.◆ The Duke assembled his whole force of about thirty-seven thousand men[146] at Marchiennes on the Scarpe on the 13th of August, and on the 15th marched in two columns north-west by Baisieux and Tourcoing upon Menin. From Baisieux the route lay across the front of the great fortress of Lille, and of the French fortified posts extending from that city to Dunkirk; ◆Aug. 18.◆ and on the morning of the 18th, soon after the advanced guard of the southern column had moved from Tourcoing, heavy firing was heard in the direction of Linselles, about two miles to the west of that place. The Prince of Orange, for reasons best known to himself, had seized the opportunity to sally out from Menin, and surprise the French posts of Blaton and Linselles, which being accomplished, he left two weak battalions to hold them, and retired. About mid-day the French returned with five thousand men and drove out the Dutch; and an hour or two later an aide-de-camp came galloping into Menin to ask for help. The Duke of York at once ordered out the brigade of Guards, which had just arrived at Menin after a severe march, with a few guns, under General Lake. The three battalions, without their flank companies, and therefore little over eleven hundred strong, at once turned out, and traversed the six miles to Linselles in little more than an hour, but, on reaching it, found not a Dutchman there. They were, however, saluted by a heavy fire of grape from batteries which they had supposed to be in possession of the Dutch; and thereupon Lake determined to attack at once.