The Battle of Eckmühl, fought on 21 April–22 April 1809, was the turning point of the 1809 Campaign, also known as the War of the Fifth Coalition. Napoleon I had been unprepared for the start of hostilities on 10 April 1809, by the Austrians under the Archduke Charles of Austria and for the first time since assuming the French Imperial Crown had been forced to give up the strategic initiative to an opponent. Thanks to the dogged defense waged by the III Corps, commanded by Marshal Davout, and the Bavarian VII Corps, commanded by Marshal Lefebvre, Napoleon was able to defeat the principal Austrian army and wrest the strategic initiative for the remainder of the war.