ABSTRACT
From 1939 to 1941 the German army seemed invincible. The Polish campaign provided a textbook example of Germany's new military doctrine of Blitzkrieg (lightning war). German military technology was vastly superior to that of the Poles. Supported by heavy artillery and squadrons of dive bombers, German armored and motorized columns rapidly pierced the Polish lines and encircled the enemy forces. The Germans would later also make innovative use of paratroopers dropped behind enemy lines. The infantry followed to carry out mopping-up operations. Some sixty German divisions participated in the invasion. German troops reached Warsaw on 9 September, and by 16 September the capital was surrounded. On 17 September the Soviet army crossed Poland's eastern borders to claim the share of Polish territory allotted to them in the Nazi-Soviet Pact. Warsaw surrendered on 27 September after heavy German bombardment. On 5 October all Polish resistance ceased.
