Polish September Campaign

Polish September Campaign. The invasion of Poland by Nazi Germany that began on 1 September 1939 marked the start of World War II in Europe. Following the secret protocols of the Molotov–Ribbentrop Pact, the Soviet Union invaded from the east on 17 September, leading to the partition of the country. Despite fierce resistance, Polish forces were overwhelmed by the combined Blitzkrieg tactics of the Wehrmacht and the Soviet advance, culminating in the final battles in early October.

Background

The campaign’s origins lie in the aggressive expansionist policies of Adolf Hitler and the Nazi Party, which demanded the annexation of the Free City of Danzig and territorial concessions across the Polish Corridor. These demands were formalized in the Gleiwitz incident, a staged attack used as a pretext for invasion. Diplomatically, Poland was allied with Britain and France through the Anglo-Polish military alliance and the Franco-Polish alliance (1921), though these guarantees proved insufficient to deter aggression. The pivotal enabling factor was the signing of the Molotov–Ribbentrop Pact between Germany and the Soviet Union, which contained secret protocols dividing Eastern Europe into spheres of influence.

Opposing forces

The Polish Armed Forces, commanded by Marshal Edward Rydz-Śmigły, fielded a large but technologically outmatched military, relying on cavalry brigades and outdated aircraft like the PZL.23 Karaś. Key formations included the Pomorze Army, Poznań Army, and Kraków Army. The German invasion force, under overall direction of Fedor von Bock and Gerd von Rundstedt, deployed two army groups utilizing revolutionary combined-arms Blitzkrieg tactics. Their arsenal included advanced Panzer divisions, the Luftwaffe with aircraft like the Junkers Ju 87, and significant contributions from the Slovak Army. The subsequent Soviet invasion was executed by the Belorussian and Ukrainian Fronts under commanders like Mikhail Kovalyov.

Course of the campaign

The campaign opened with the Battle of Westerplatte and the bombing of Wieluń on 1 September. Major early engagements included the Battle of the Border, the heroic defense at the Battle of Wizna, and the large-scale Battle of the Bzura, where the Poznań Army and Pomorze Army launched a major counter-offensive. German forces rapidly advanced, leading to the siege and eventual fall of Warsaw after heavy bombardment. The Soviet invasion on 17 September, in accordance with the Molotov–Ribbentrop Pact, made any organized defense untenable. Final resistance was crushed at the Battle of Kock, with the last major Polish units surrendering by 6 October.

Aftermath

The defeat led to the division of Polish territory between Germany and the Soviet Union, as outlined in the German–Soviet Frontier Treaty. The occupying powers instituted brutal regimes, with atrocities beginning immediately, exemplified by the Intelligenzaktion and the Katyn massacre. The Polish government-in-exile was established in Paris, later moving to London, and continued the struggle through the Polish Armed Forces in the West. Within occupied Poland, the largest resistance movement in Europe, the Home Army, was formed. Thousands of Polish military personnel escaped to neighboring countries, with many later fighting in campaigns such as the Battle of Britain and the Battle of Monte Cassino.

Significance and legacy

The campaign demonstrated the devastating effectiveness of Blitzkrieg and combined-arms warfare, a template used in subsequent German invasions like the Battle of France. It shattered the illusion of appeasement and formally began the European theatre of World War II, leading to declarations of war by Britain and France. The dual invasion by both totalitarian powers defined the character of the war in Eastern Europe and began a period of immense suffering for the Polish people. The conflict’s legacy is memorialized in Poland through sites like the Museum of the Second World War in Gdańsk and annual observances of the Warsaw Uprising anniversary, while its geopolitical consequences directly shaped the post-war division of Europe at conferences like Yalta.

Category:World War II Category:Invasions Category:Military history of Poland