September Campaign (Poland)

September Campaign (Poland) The September Campaign of 1939 was the joint German and Soviet invasion that precipitated World War II. It began with the German invasion on 1 September 1939 and was followed by the Soviet intervention on 17 September 1939, resulting in the partition of the Second Polish Republic under the Molotov–Ribbentrop Pact.

Background

In the months preceding September 1939 tensions rose as leaders negotiated and prepared for war. The Nazi Adolf Hitler regime pursued expansion following the Anschluss, the Munich Agreement involving Neville Chamberlain and Édouard Daladier, and the annexation of the Sudetenland. The Polish government under Ignacy Mościcki and military planners including Edward Rydz-Śmigły sought guarantees from United Kingdom and France after the occupation of Czechoslovakia; those guarantees led to declarations of war on Germany by Winston Churchill’s predecessors and French leaders following the invasion. Meanwhile the USSR under Joseph Stalin concluded the Molotov–Ribbentrop Pact with Vyacheslav Molotov and Joachim von Ribbentrop, containing secret protocols that affected Baltic States and Polish territory. German forces mobilized units from regions including Silesia, Pomerania, and East Prussia, while Polish units prepared defensive positions along the Warta River and near Warsaw.

Course of the Campaign

The campaign opened with the Blitzkrieg thrusts: the Wehrmacht launched operations including Fall Weiss concentrating on thrusts from East Prussia toward Warsaw, from Silesia toward Cracow, and from Pomerania toward Danzig. Early actions included the Battle of Westerplatte at the Gdańsk Harbor, the Battle of the Bzura counterattack, and fighting around Modlin Fortress and Wawer. Polish forces under Tadeusz Kutrzeba and Józef Haller attempted strategic withdrawals toward Lublin and Lviv, while the Polish Navy executed operations from Hel Peninsula and ships including ORP Błyskawica moved to allied ports. As British Expeditionary Force plans and French plans failed to materialize offensively, German panzer units under commanders such as Heinz Guderian encircled Polish armies, culminating in the siege of Warsaw and capitulations at Tomaszów Mazowiecki. The Soviet entry from the east under Soviet Union command sealed Polish strategic collapse; fighting continued in pockets such as the Battle of Kock before organized resistance ended and formal surrender and occupation arrangements were implemented.

Combatant Forces and Commanders

The belligerents included Third Reich forces under commanders like Heinz Guderian, Walther von Brauchitsch, and Fedor von Bock deploying formations such as Heer panzer and infantry divisions alongside Luftwaffe air units led by figures including Hermann Göring. The Polish Army comprised armies and corps commanded by leaders including Edward Rydz-Śmigły, Tadeusz Kutrzeba, Władysław Sikorski, and Józef Beck, fielding infantry, cavalry brigades, and coastal units. The Soviet Union employed Red Army formations under the political and military direction of Joseph Stalin and ministers including Kliment Voroshilov and Semyon Timoshenko. Allied political and military responses involved the United Kingdom under Neville Chamberlain and the French Republic under Édouard Daladier, whose declarations of war contrasted with limited ground operations like the Saar Offensive.

Civilian Impact and Occupation

Civilian populations across Poland experienced displacement, reprisals, and administrative change under occupation authorities. German occupation policy implemented territorial annexation into provinces such as Reichsgau Danzig-West Prussia and mass actions by organizations including the SS, Gestapo, and Einsatzgruppen that targeted Jewish communities and Polish intelligentsia in operations comparable to Intelligenzaktion. The Soviet administration in eastern areas carried out arrests, deportations to locations like Siberia and Krasnoyarsk Krai, and political purges associated with NKVD actions. Cities including Warsaw, Łódź, Lublin, and Vilnius faced curfews, occupation bureaucracies, and economic requisitions; cultural institutions such as Jagiellonian University and University of Warsaw saw suppression. Refugee flows affected neighboring countries including Romania and Hungary, and organizations such as Red Cross attempted relief amid contested corridors and internments.

Aftermath and Consequences

The campaign resulted in the division of the Second Polish Republic between Nazi Germany and the Soviet Union in accordance with the Molotov–Ribbentrop Pact, the establishment of the General Government, and the internment and exile of Polish political and military leaders who later formed the Polish government-in-exile and the Polish Armed Forces in the West under figures like Władysław Sikorski. The occupation set the stage for systematic Holocaust persecutions, the Katyn massacre associated with NKVD executions, and long-term geopolitical shifts culminating in conferences such as Tehran Conference, Yalta Conference, and postwar arrangements settled at Potsdam Conference. The campaign’s outcome influenced subsequent campaigns including the Battle of France and reshaped alliances among the Allies of World War II and the Axis powers.

Category:Invasions of Poland Category:1939 in Poland Category:Battles and operations of World War II