In the beginning of March, immediately after the congress broke up, the siege of Mons was undertaken by the French king in person, accompanied by the Dauphin, the dukes of Orleans and Chartres.

The garrison consisted of about six thousand men, commanded by the prince of Bergue: but the besiegers carried on their works with such rapidity as they could not withstand.

King William no sooner understood that the place was invested, than he ordered prince Waldeck to assemble the army, determined to march against the enemy in person.

Fifty thousand men were soon collected at Halle, near Brussels: but when he went thither, he found the Spaniards had neglected to provide carriages, and other necessaries for the expedition.

Meanwhile, the burghers of Mons, seeing their town in danger of being utterly destroyed by the bombs and cannon of the enemy, pressed the governor to capitulate, and even threatened to introduce the besiegers: so that he was forced to comply, and obtained very honourable conditions.