The Battle of Abensberg took place on 20 April 1809, between a Franco-German force under the command of Emperor Napoleon I of France and a reinforced Austrian corps led by Feldmarschall-Leutnant Archduke Louis of Austria. As the day wore on, Feldmarschall-Leutnant Johann von Hiller arrived with reinforcements to take command of the three corps that formed the Austrian left wing. The action ended in a complete Franco-German victory. The battlefield was southeast of Abensberg and included clashes at Offenstetten, Biburg-Siegenburg, Rohr in Niederbayern, and Rottenburg an der Laaber. On the same day, the French garrison of Regensburg capitulated.