Battle of Nördlingen
Following the Swedish defeat at the Battle of Nördlingen in 1634, Bernhard's mercenary army had come under the pay of France. Having been pushed to the west bank of the Rhine by the Imperial advance, Bernhard's army had settled in Alsace during 1635 and had done little except help repulse the Imperial invasion of France under the Cardinal-Infante Ferdinand and Matthias Gallas in 1636.