Recognizing the need for reinforcements, and fearing his army would be flanked by Moreau's surprise crossings at Kehl and Hüningen, Charles arrived near Rastatt with more troops and prepared to advance against Moreau on 10 July. The Austrians under Archduke Charles, Duke of Teschen tried to halt the northward advance of Jean Victor Marie Moreau's French Army of Rhin-et-Moselle along the east bank of the Rhine River. The French surprised him by attacking first, on 9 July. Despite the surprise, in the Battle of Ettlingen, Charles repulsed Desaix's attacks on his right flank, but Saint-Cyr and Taponier gained ground in the hills to the east of the town, and threatened his flank. After a tough fight, the Austrian commander found that his left flank was turned. He conceded victory to the French and retreated east toward Stuttgart. Moreau lost 2,400 out of 36,000 men while Charles had 2,600 hors de combat out of 32,000 troops. Anxious about the security of his supply lines, though, Charles began a measured and careful retreat to the east.