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
18th Army (German Empire) 18th Army (German Empire) <nowiki></nowiki> The 18th Army () was an army level command of the German Army in World War I. It was formed against France on 27 December 1917 from the former Heeresgruppe Woyrsch command. It served exclusively on the Western Front and was dissolved on 2 January 1919. 18th Army was one of three armies (along with 17th Army and 19th Army) formed in late 1917 / early 1918 with forces withdrawn from the Eastern Front. They were in place to take part in Ludendorff's Spring Offensive. The Germans had realised that their only remaining chance of