By late August the "Army of Sambre-et-Meuse" faced the Austrian army of Wilhelm von Wartensleben along the Naab River with Jean-Baptiste Bernadotte's division watching its southern flank. Jourdan hoped that Moreau's Army of the Rhine and Moselle would pin down the Austrians in southern Germany, but this did not occur. On 22–23 August Bernadotte's 6,000 troops were attacked by Archduke Charles with 28,000 Austrians. Jourdan sent Bonnaud's cavalry to help, but events moved too fast and Bernadotte made a fighting retreat northwest to Forchheim. Bonnaud never joined Bernadotte and was beset by superior forces as his troopers fell back toward Jourdan's main army. In order to allow Bonnaud to escape, Jourdan stood to fight and was beaten in the Battle of Amberg on 24 August. In his retreat, Jourdan headed for Würzburg with Bonnaud's cavalry in the lead, but the Austrians got there first. On 2 September, two French divisions and the cavalry were in front of Würzburg though a third division did not appear until the evening. Charles defeated the French in the Battle of Würzburg on 3 September. The Austrians sustained 1,500 casualties while the French lost twice as many plus seven guns. The action began at 7:00 am when the left flank French division under Paul Grenier moved forward only to be attacked by a mass of Austrian cavalry. Wartensleben hurled 24 squadrons of cuirassiers at Grenier, but Bonnaud and the divisional French cavalry fought them off. When 12 additional squadrons of Austrian cuirassiers charged, Bonnaud was defeated and forced to shelter behind the French infantry. Jourdan ordered a withdrawal after being hard-pressed by Austrian reinforcements.