September Campaign

September Campaign
Ai6z83xl3g · CC BY-SA 3.0 · source
Name	September Campaign
Partof	World War II
Date	September 1 – October 6, 1939
Place	Poland
Result	Axis and Soviet victory
Combatant1	Nazi Germany; Slovakia
Combatant2	Second Polish Republic
Commander1	Adolf Hitler; Heinz Guderian; Walther von Reichenau; Erich von Manstein
Commander2	Edward Rydz-Śmigły; Ignacy Mościcki; Władysław Sikorski
Strength1	Approx. 1.8 million
Strength2	Approx. 1 million

September Campaign

The September Campaign was the 1939 invasion of Poland by Nazi Germany and later the Soviet Union, launching World War II in Europe. The operation featured coordinated assaults by formations such as the Wehrmacht panzer divisions and the Red Army's western fronts, rapid maneuvers epitomized by commanders like Heinz Guderian and strategic failures among Polish leadership including Edward Rydz-Śmigły. The campaign combined mechanized warfare, aerial bombardment by the Luftwaffe, and political actions culminating in division of Polish territory under the Molotov–Ribbentrop Pact.

Background

Tensions after the Treaty of Versailles and German revanchism under Adolf Hitler shaped Central European politics, drawing lines between Poland and Nazi Germany over territories such as the Polish Corridor and Danzig (Gdańsk). The 1934 Polish–Romanian alliance and diplomatic exchanges with France and the United Kingdom informed Polish expectations, while the signing of the Molotov–Ribbentrop Pact between the Soviet Union and Nazi Germany created secret protocols for partitioning Eastern Europe. Strategic doctrines from the German General Staff and innovations by officers like Erich von Manstein and Heinz Guderian favored Blitzkrieg, while Poland’s defenses based on the Fortified Area of Modlin and the Polish Army’s mobilization plans faced constraints from political leaders such as Ignacy Mościcki and Józef Beck.

Opposing forces

On the Axis side, forces included the Wehrmacht Heer, the Luftwaffe, and formations from Slovak contingents, with senior figures like Walther von Reichenau directing northern operations and Gerd von Rundstedt active in command roles. German units deployed panzer divisions from the Heeresgruppe Süd and Heeresgruppe Nord, supported by motorized infantry and Stuka dive bomber formations commanded by leaders connected to the Oberkommando der Wehrmacht. The Polish Army fielded infantry, cavalry brigades, and armored units such as the 10th Motorized Cavalry Brigade under commanders linked to Władysław Sikorski and regional commanders around Kraków and Warsaw. Later, the Red Army invaded from the east under directives tied to the Soviet Politburo and commanders operating within the Western Military District and Belorussian Military District.

Course of the campaign

On September 1, German forces crossed the Polish] border with coordinated assaults against border fortifications, employing combined-arms tactics tested during maneuvers in the Weimar Republic era. Early battles included the Battle of Westerplatte, the Battle of the Bzura, and the Siege of Warsaw, where urban defense involved units withdrawing from positions near Kielce and Toruń. Mechanized formations executed rapid encirclements, cutting communications between centers like Lwów and Wilno. The Luftwaffe targeted rail hubs and civilian centers, while armored spearheads under commanders such as Heinz Guderian pushed toward the Vistula River. The Battle of Bzura represented the largest Polish counterattack but ended in retreat. On September 17, following the Molotov–Ribbentrop Pact secret protocols, the Soviet Union began operations from the Brest-Litovsk area, linking with German advances and accelerating collapse of organized Polish resistance, culminating in the surrender of Warsaw on September 27 and final capitulations by early October.

Civilian impact and atrocities

Civilian populations suffered from aerial bombing campaigns and reprisals in towns such as Częstochowa, Gdynia, and Gdańsk, resulting in significant casualties and infrastructure destruction. The campaign saw documented war crimes including the Massacre of Zakroczym and actions against prisoners and civilians that prefigured later Nazi occupation of Poland policies; perpetrators included elements of the Wehrmacht and Gestapo supported by units tied to organizations like the SS. The Soviet Union carried out arrests and deportations in eastern territories, with NKVD operations targeting officials, intelligentsia, and families in regions such as Kresy and Wilno. Episodes of anti-Jewish violence occurred alongside state actions, affecting communities in cities like Kraków and Lwów and foreshadowing measures later codified under occupation administrations including the General Government.

Diplomatic and international response

The invasions prompted declarations of war by the United Kingdom and France on Nazi Germany, invoking treaty commitments to Poland, yet immediate military assistance to Polish forces was limited; plans such as the Saar Offensive and Franco-British operations failed to produce decisive relief. Diplomatic communications involved envoys and foreign ministers including figures from London, Paris, and Moscow, and were influenced by policies from the League of Nations and reactions in capitals like Rome and Washington, D.C.. Some states such as Romania and Hungary adjusted policies to accommodate refugee flows, while neutral countries like Sweden and Switzerland engaged in humanitarian and diplomatic initiatives. The Molotov–Ribbentrop Pact's exposure of secret protocols generated alarm among governments in Bucharest and Belgrade.

Aftermath and legacy

The campaign resulted in the partition of Poland under occupation by Nazi Germany and the Soviet Union, establishment of the General Government, and the exile of Polish political and military leadership to France and later United Kingdom, contributing to formations like the Polish Armed Forces in the West. The experience shaped subsequent campaigns including the Battle of France and influenced doctrines in the Red Army and Wehrmacht, while legal and historical assessments of wartime atrocities informed postwar tribunals such as the Nuremberg Trials and influenced border settlements ratified at conferences like Yalta Conference and Potsdam Conference. Memory of the campaign persists in Polish commemorations, museums such as the Warsaw Uprising Museum and national narratives involving figures like Władysław Sikorski and Józef Piłsudski's legacy, and continues to inform scholarship in institutions such as Polish Academy of Sciences and studies at universities across Europe.

Category:Invasions of Poland