German invasion of Poland (1939)

German invasion of Poland (1939)
Conflict	German invasion of Poland
Partof	World War II
Caption	Invasion map, September 1939
Date	1–6 September 1939 (initial phase) – 6 October 1939 (campaign end)
Place	Poland, Free City of Danzig, Memel Territory
Result	German victory, Soviet invasion of Poland (17 September 1939)
Territory	Division of Second Polish Republic between Nazi Germany and the Soviet Union

German invasion of Poland (1939) The German invasion of Poland in 1939 was a short, decisive campaign that triggered World War II in Europe. Initiated by Nazi Germany under Adolf Hitler and executed by the Wehrmacht, the operation used combined arms and airpower against the Second Polish Republic, culminating in occupation and territorial partition with the Soviet Union. The invasion entwined with diplomatic crises involving United Kingdom, France, Italy, Japan, Romania, and Hungary.

Background and Causes

The invasion emerged from Nazi ideology espoused in Mein Kampf and expansionist aims tied to Lebensraum and revision of the Treaty of Versailles. Hitler's demands over the Free City of Danzig and the Polish Corridor followed diplomatic crises like the Remilitarization of the Rhineland and the Anschluss of Austria. The Munich Agreement and appeasement policies of Neville Chamberlain, Édouard Daladier, and Daladier's cabinet weakened deterrence, while German rearmament under Hermann Göring and the Reichswehr–Wehrmacht reforms by Werner von Blomberg and Walther von Brauchitsch shifted the balance. Bilateral pacts such as the German–Soviet Nonaggression Pact (Molotov–Ribbentrop Pact) and the secret protocols dividing spheres with Vyacheslav Molotov and Joachim von Ribbentrop removed the threat of a two-front war and emboldened Hitler. Polish diplomatic ties with United Kingdom and France—the Anglo-Polish military alliance and the Franco-Polish alliance—failed to deter invasion after the fall of Czechoslovakia.

Prelude and Mobilization

In summer 1939 the Wehrmacht undertook the Operation Himmler false-flag operations, including staged incidents like the Gleiwitz incident, to fabricate justification. German mobilization, directed by OKW and OKH, synchronized with Luftwaffe preparations under Hermann Göring and naval deployments including the Kriegsmarine. Poland placed forces under Edward Rydz-Śmigły and Marshal Józef Piłsudski's successors, mobilizing units including the Polish Army (1939) and border guards, while relying on reserve plans and fortifications at Modlin Fortress and the Westerplatte. Diplomatic moves involved British guarantee to Poland and urgent appeals to Paris; however, French Army (Third Republic) mobilization lagged. Secret protocols of the Molotov–Ribbentrop Pact prepared the Soviet invasion of Poland and influenced Soviet mobilization under Joseph Stalin.

Course of the Invasion

Hostilities began on 1 September 1939 with coordinated strikes: Blitzkrieg tactics featured rapid panzer thrusts by units such as the Panzerwaffe across the Vistula and seizures of key nodes like Warsaw air raids, Łódź, and Kraków campaigns. Early battles included Battle of the Bzura, the defensive fight at Westerplatte, the Battle of Mokra, and urban combat in Toruń and Kielce. The Luftwaffe executed strategic bombing against Polish Aviation targets and civilian centers including Przemyśl and Gdynia harbour, while the Kriegsmarine enforced blockades. The Polish counteroffensive at the Battle of Bzura briefly disrupted German advances but was encircled by panzer divisions from Wehrmacht commanders such as Heinz Guderian and Erich von Manstein. After heavy fighting the Siege of Warsaw ended with capitulation; subsequent operations secured Eastern Galicia and Podlaskie. The campaign concluded after the Soviet invasion of Poland on 17 September and the surrender of organized Polish resistance by early October.

Military Forces and Tactics

German forces employed combined arms doctrine integrating Panzer I, Panzer II, Panzer III, Stuka dive bomber support, motorized infantry, and signals coordination pioneered by the Heer and General Staff (Germany). German tactics emphasized encirclement (Kesselschlacht) and rapid operational movement (Schlachtordnung) executed by units like the 14th Army and 10th Army. Polish defense relied on Polish cavalry brigades, 7TP tank, PZL P.11 fighters, and fortifications at sites like Hel Peninsula; logistics suffered from shortages exacerbated by interrupted rail networks and telegraph lines. Intelligence roles involved Abwehr operations and Polish cryptographic efforts; both sides experienced air superiority battles involving Luftwaffe squadrons and Polish Air Force escadrilles.

Civilian Impact and Atrocities

The invasion caused widespread civilian casualties, infrastructure destruction, and refugee flows to Romania and Hungary. German forces and auxiliary units committed atrocities including massacres in places like Bromberg (Bydgoszcz), executions of prisoners, and reprisals under directives influenced by Heinrich Himmler and Reinhard Heydrich. Persecution targeted Polish Jews and intelligentsia; early measures foreshadowed later policies such as the Generalplan Ost and the Intelligenzaktion. Bombing of towns like Wieluń constituted some of the war's first attacks on civilians. The invasion precipitated humanitarian crises reported by organizations such as the International Red Cross and prompted emigration of political and military leaders to France and United Kingdom.

International Response and Diplomacy

Diplomatic reactions included British and French ultimatums that resulted in declarations of war on 3 September 1939 by United Kingdom and France, yet lacked immediate coordinated offensive action (the Phoney War). Italy and Japan observed Axis diplomacy, while neutral states like Sweden and Switzerland maintained non-belligerent stances. The Soviet Union's entry via the Molotov–Ribbentrop Pact reshaped the diplomatic map, with the Baltic states and Finland affected. International legal debates referenced the Treaty of Versailles and conventions such as the Hague Conventions, while debates in the League of Nations and statements from leaders like Winston Churchill and Édouard Daladier framed subsequent Allied strategy.

Aftermath and Occupation Policies

Following military defeat, Poland was partitioned: Reichsgau Danzig-West Prussia, General Government, and Soviet-annexed territories were established, with puppet administrations and annexations enforced by Hans Frank and Arthur Greiser. Occupation policies implemented ethnic cleansing, forced labor deportations to Reich, property seizures, and cultural suppression aimed at liquidation of Polish elites and Jewish ghettos, presaging the Holocaust. Polish government-in-exile formed in London under Władysław Sikorski and maintained military formations in the Western Desert and on the Western Front. The invasion set patterns for subsequent Axis occupations and influenced Allied strategic decisions at conferences like the later Tehran Conference and Yalta Conference.

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