The twenty years of fighting that followed the French Revolution, and into which all Europe was drawn, were everywhere accompanied by outbreaks of pestilence, many of which were very serious. At the very beginning of the first Coalition War (1792–7) they played an important rôle. A severe epidemic of dysentery broke out among the Prussian troops when they were advancing into Champagne, and this was chiefly responsible for the failure of the invasion. Typhus fever had also appeared and caused a great many deaths among the Prussians, as well as among the inhabitants of the Departments of Meuse, Moselle, Meurthe, and Ardennes.[78] When the badly infected army of the Allies retreated, after the engagement at Valmy (September 20, 1792), it left behind its sick in various cities and villages, and thus infected the French army that followed in pursuit. In Longwy itself (which had remained in the power of the Allies until October 22), and in the immediate vicinity, the streets were filled with the bodies of soldiers who had succumbed, partly to exhaustion, and partly to dysentery.[79] Verdun suffered terribly during the siege of the Allies, and at the end of August was obliged to surrender. The chief cause of the widespread occurrence of disease there was the fearful lack of sanitation; ‘à Verdun,’ say Maréchal and Didion[80] ‘une des causes les plus puissantes d’infection était le dépavement de la ville au moment du siège. Tous les jours on jetait de chaque maison au milieu de la rue des immondices de toute espèce, des déjections humaines et animales, des débris, des végétaux, qui se mêlant à la boue se liquéfiaient et se putréfiaient par l’action des pluies. Les agents de la ferme des boues ne pouvaient rien contre tel foyer. Il s’en échappait une odeur infecte, quand quelque voiture venait à passer, et l’on voyait souvent des personnes frappées de spasmes, prises de vomissements et même asphyxiées en traversant les rues.’ (One of the most potent causes of the infection at Verdun was the unpaved state of the town at the time of the siege. Every day refuse of all kinds was thrown from each house out into the street—the evacuations of men and animals, rubbish, and garbage—and there it mixed with the mud, liquefied and rotted through the action of the rain. The officials in charge of street sanitation were powerless. All this filth emitted a foul odour when a carriage drove through it, and one often saw people seized with convulsions and sickness, or even suffocated while crossing the streets.) There was no more thought of taking proper care of the sick and wounded in Verdun at that time, than there was in the later French wars; they lay in numbers on rotten straw, in their own excrement, two or three of them sharing a single blanket. The result was that two-thirds of the patients died.