I Corps under Heinrich Graf von Bellegarde, consisting of 38,000 troops, and the II Corps of 20,000 troops under Johann Kollowrat, to attack Regensburg (Ratisbon) from the Bohemian mountains by way of Cham. The Austrian center and reserve, comprising 66,000 men of Hohenzollern's III Corps, Rosenberg's IV Corps, and Lichtenstein's I Reserve Corps, would advance on the same objective through Scharding. The left wing, made up of the V Corps of Archduke Louis, Hiller's VI Corps, and Kienmayer's II Reserve Corps, a total of 61,000 men, would move toward Landshut and guard the army's flank. Two other theatres would be opened in Poland and Italy. Historian Steven Englund considers that Austria "might well have won the campaign" if the nation had focused on Germany. French preparations The French army mostly consisted of veterans of Napoleon's earlier campaigns, though recent conscripts formed large parts of some units, negatively affecting their fighting ability. The army was enthusiastic and keen to fight well under Napoleon's direct leadership. Napoleon was not certain about Austrian planning and intentions. He returned to Paris from his campaigns in Spain in winter 1808–09 and instructed the main French field commander in southern Germany, Louis Alexandre Berthier, on planned deployments and concentrations for this likely new second front. His rough ideas about the possible upcoming campaign included the decision to make the Danube valley the main theatre of operations, as he had done in 1805, and to stop Austrian forces that might invade northern Italy by positioning some of his own forces under the command of Eugène de Beauharnais and Auguste Marmont. Faulty intelligence gave Napoleon the impression that the main Austrian attack would come north of the Danube. On 30 March, he wrote a letter to Berthier explaining his intention to mass 140,000 troops in the vicinity of Regensburg (Ratisbon), far to the north of where the Austrians were planning to make their attack. It was expected that this redeployment would take until mid-April to accomplish and Napoleon instructed Berthier that if the attack came before 15 April he was to fall back towards the Lech. Austria–Bavaria front Austria strikes first The first indication of an Austrian attack was a formal note sent by Archduke Charles to French Marsal François Joseph Lefebvre on 9 April. It stated that Charles had orders from Francis to invade Bavaria, a French client state under Maximilian I. In the early morning of