The retreat of the French, enabled the enemy to turn his whole force upon the Swedes in Bohemia. Gustavus Wrangel, no unworthy successor of Banner and Torstensohn, had, in 1646, been appointed Commander-in-chief of the Swedish army, which, besides Koenigsmark's flying corps and the numerous garrisons disposed throughout the empire, amounted to about 8,000 horse, and 15,000 foot. The Archduke, after reinforcing his army, which already amounted to 24,000 men, with twelve Bavarian regiments of cavalry, and eighteen regiments of infantry, moved against Wrangel, in the hope of being able to overwhelm him by his superior force before Koenigsmark could join him, or the French effect a diversion in his favour. Wrangel, however, did not await him, but hastened through Upper Saxony to the Weser, where he took Hoester and Paderborn. From thence he marched into Hesse, in order to join Turenne, and at his camp at Wetzlar, was joined by the flying corps of Koenigsmark. But Turenne, fettered by the instructions of Mazarin, who had seen with jealousy the warlike prowess and increasing power of the Swedes, excused himself on the plea of a pressing necessity to defend the frontier of France on the side of the Netherlands, in consequence of the Flemings having failed to make the promised diversion. But as Wrangel continued to press his just demand, and a longer opposition might have excited distrust on the part of the Swedes, or induce them to conclude a private treaty with Austria, Turenne at last obtained the wished for permission to join the Swedish army.