Operating over a fifty mile front, from Ratisbon to Pfaffenhofen (district), marked by stretches of rugged, wooded terrain, neither the French nor the Austrians had developed adequate intelligence about their opponent's strength, dispositions or intentions. Assuming that the bulk of the Austrian army was deployed so as to cover their bridgehead at Landshut and the main highway to Vienna, on 20 April 1809, Napoleon launched most of his army in an attack to the Southwest. The resulting Battle of Abensberg was a clear, French victory, following which Napoleon ordered all but Davout's III Corps and Lefebvre’s (Bavarian) VII Corps to pursue and destroy what he thought was the remains of the Austrian Army.