The Catholic powers had long been privately urging upon him the danger that would arise should Austria be crushed.  The Swedes would acquire very large accessions of territory, the Protestant German princes, their allies, would similarly benefit, and Protestantism would become the dominant religion in Germany.  Such would, indeed, have undoubtedly been the case had the allies marched to Vienna and dictated terms of peace there.  An order was therefore sent to Turenne to march with his army to Flanders, where the Spaniards were gaining great advantages, as Enghien, now become Prince of Conde by the death of his father, had been sent into Catalonia with the greater portion of his army.  Turenne, foreseeing that his German regiments would refuse to march to Flanders, leaving their own country open to invasion and plunder by the Imperialists, warmly opposed the plan, and sent messenger after messenger to the cardinal urging him to countermand the order.  The friends of Bavaria and the Catholic princes urged strongly upon the queen that the continuance of the war would utterly destroy the Catholic religion in Germany, and that the Swedes alone would reap advantage from the fall of the house of Austria.  Moved by their arguments and those of Mazarin to the same effect, she supported the latter, and peremptory orders were sent to Turenne to march to Flanders, where matters were going from bad to worse.  Turenne obeyed them, captured on his march towards the Rhine several towns and fortresses, destroying their fortifications so that they would not be able to oppose him if he returned to Germany.  But on arriving on the Rhine his anticipations of trouble were fulfilled.  General Rosen, whose blunder had been the cause of the disaster at Marienthal, and who had since his return from captivity persistently worked in opposition to Turenne, fomented discontent among the troops of Weimar, and directly they crossed the Rhine they absolutely refused to advance.  They had just cause for complaint; they had fought with distinguished valour, and they alone had saved the French army from suffering crushing defeat at Nordlingen; their pay was six months in arrear, and the proposal now that they should leave their own country and fight in Flanders was naturally most repugnant to them.  They at once marched away towards Strasburg.  Turenne followed them with three thousand infantry, four French regiments of horse, and the only one of the Weimar cavalry that had remained faithful to him, and came up just as they were about to recross the Rhine.

Partly by entreaties, partly by showing his confidence in them, by putting himself wholly in their power, the marshal induced a portion of the Weimar cavalry to return to their duty.  General Rosen, who was to a large extent responsible for the mutiny, was arrested and imprisoned at Philippsburg, the rest of the mutineers rode away with the loss of a portion of their number, and joined the Swedes.  After this the order for Turenne to march to Flanders was countermanded.