British war crimes September 1915 and continued their usage for the remainder of the war. This was done in retaliation for the use of chlorine by Imperial German Army the preceding April. Following the Imperial German Army's use of poison gas at Ypres, the commander of II Corps, Lieutenant General Sir Charles Ferguson, had said of poison gas: Mustard gas was first used effectively in World War I by the German army against British and Canadian soldiers near Ypres, Belgium, in 1917 and later also against the French Second Army. The name "Yperite" comes from its usage by the German army near the
Opposing forces in the Polish September Campaign Poland successfully used 10 regular armoured trains against German forces, which were unprepared to face this kind of combat vehicle considered in 1939 so obsolete by German planners to be given any serious consideration. Although the trains proved indeed vulnerable to air attack, losses incurred against Polish trains ("Śmiały" Armored Train destroyed nearly 100 German tanks during the battles around Mokra village) convinced the Germans to reintroduce this type of vehicle into their own army after the September Campaign. Experience in the Polish-Soviet War (1919–1921), the only recent, major conflict the independent Second Polish Republic took part in, shaped Polish