On October 14, 1781, Baron Antoine de Vioménil commanded the French attack on Redoubt 9, defended by approximately 120 British and German troops. He chose Colonel en Second Guillaume de Forbach des Deux-Ponts, also known as Wilhelm von Forbach, to lead a 400-man assault drawn from the Gâtinais and Royal Deux-Ponts Regiments, the latter also known as Das Deutsche Königlich Französische Infantrie Regiment von Zweibrücken. The French advance was delayed when engineering troops suffered heavy casualties clearing obstructions along the British perimeter, and the attack was further complicated by darkness, close-quarters fighting, similar German uniforms on both sides, and confusion caused by German commanders among both attackers and defenders. Within 30 minutes, however, Vioménil congratulated Deux-Ponts on taking the redoubt, removing the last obstacle to the Allies completing their Second Siege Line.
