Ypres east of the town. The first gas attack occurred against Canadian, British, and French soldiers, including both metropolitan French soldiers as well as Senegalese and Algerian tirailleurs (light infantry) from French Africa. The gas used was chlorine. Mustard gas, also called Yperite from the name of this town, was also used for the first time near Ypres, in the autumn of 1917. Of the battles, the largest, best-known, and most costly in human suffering was the Third Battle of Ypres (31 July to 6 November 1917, also known as the Battle of Passchendaele), in which the British, Canadian, ANZAC, and
Actions of 30 September – 4 October 1917 diary note that it had been an awful experience; he did not know what to do against the British. Erich Ludendorff the (Quartermaster-General of the German Army, equivalent to the British Chief of the General Staff) conferred on 29 September with (field marshal) Crown Prince Rupprecht the commander and (lieutenant-general) Hermann von Kuhl the chief of staff, of "Heeresgruppe Kronprinz Rupprecht von Bayern" (Army Group Rupprecht of Bavaria), the 4th Army commander, General Sixt von Armin and the 4th Army chief of staff, (major-general) Fritz von Loßberg. The staff officers of the 4th Army (corps headquarters) agreed that defensive manoeuvres