The Battle of Herbsthausen, or the Battle of Mergentheim, was fought on 2 May 1645. The battle was between French forces led by Marshal Turenne and the Bavarian army led by Franz von Mercy. The French had caught the Bavarians short of troops at the beginning of the campaigning season, and pursued the Bavarians deep into Württemberg, but the Bavarians caught the French unawares and heavily defeated them.