The French generals had owed their brilliant successes in part to the speed of their movements, in part also to the defenceless state of the countries invaded. During the winter Frankfort had been stormed by the Prussians (December 2, 1792), and Custine had been driven back to the Rhine. For the recovery of Belgium and the territory of the Empire on the left bank of the river, Austria and Prussia brought together more than 200,000 men, and these formed two armies. The northern, commanded by an Austrian, Coburg, was to operate against Belgium; the southern, commanded by the Duke of Brunswick, was to besiege Mainz, and to drive Custine out of the Palatinate. The French government authorised Dumouriez to invade Holland, though the probabilities of success were now small. Coburg was advancing towards the Meuse, and the Dutch were prepared to defend the passage of their rivers. Dumouriez had only 100,000 men for purposes of defence and invasion. He made a rapid march through the west of Flanders as far as the arm of the sea which forms the mouth of the Meuse, where he was checked by want of means of transport. Meanwhile one of his officers, Miranda, guarded the line of the Meuse and besieged Maestricht. Coburg advanced and relieved the town. The French troops, three-fourths of whom were untrained volunteers, fled in disorder and deserted by thousands. The pursuit, however, was not closely pressed, and Miranda, rallying his scattered forces, took up a strong position near Louvain. ♦Revolutionary Court.♦