 The Imperials and the Catholic League were facing increasingly severe pressure in the war from the French, Swedes and their Protestant allies and were struggling to prevent a French attempt to advance into Bavaria.The 12,000-man Imperial-Bavarian army, led by Field Marshal Franz Baron von Mercy and Johann von Werth entrenched on rising ground near the village of Alerheim, 10 km southeast of Nordlingen.One km to the northeast of the village, the ridge rises to a height called the Wennenberg.