<p>Poles walk among the ruins of besieged <a href="/narrative/2014">Warsaw</a>.</p>
<p>This photograph documenting war destruction was taken by <a href="/narrative/11384">Julien Bryan</a>  (1899-1974), a documentary filmmaker who filmed and photographed the everyday life and culture of individuals and communities in various countries around the globe.</p>

Invasion of Poland, Fall 1939

German troops invaded Poland on September 1, 1939, triggering World War II. In response to German aggression, Great Britain and France declared war on Nazi Germany.

Key Facts

  • 1

    Nazi Germany possessed overwhelming military superiority over Poland. The assault on Poland demonstrated Germany’s ability to combine air power and armor in a new kind of mobile warfare.

  • 2

    On September 17, 1939, the Soviet Union invaded eastern Poland, sealing Poland’s fate. The last operational Polish unit surrendered on October 6.

  • 3

    After Poland’s defeat in early October 1939, Nazi Germany and the Soviet Union divided the country in accordance with a secret clause in the German-Soviet Non-Aggression Pact.

Hitler's Non-Aggression Pact with Poland

One of Adolf Hitler's first major foreign policy initiatives after coming to power was to sign a nonaggression pact with Poland in January 1934. This move was unpopular with many Germans who supported Hitler but resented the fact that Poland had received the former German provinces of West Prussia, Poznan, and Upper Silesia under the Treaty of Versailles. However, Hitler sought the non-aggression pact in order to neutralize the possibility of a French-Polish military alliance against Germany before Germany had a chance to rearm.

Appeasement in Europe

In the mid and late 1930s, France and especially Britain followed a foreign policy of appeasement, a policy closely associated with British prime minister Neville Chamberlain. The objective of this policy was to maintain peace in Europe by making limited concessions to German demands. In Britain, public opinion tended to favor some revision of the territorial and military provisions of the Versailles treaty. Moreover, neither Britain nor France felt militarily prepared to fight a war against Nazi Germany in 1938.

German gains, 1936-1938

Britain and France essentially acquiesced to Germany's rearmament (1935-1937), remilitarization of the Rhineland (1936), and annexation of Austria (March 1938). In September 1938, after signing away the Czech border regions, known as the Sudetenland, to Germany at the Munich conference, British and French leaders pressured France's ally, Czechoslovakia, to yield to Germany's demand for the incorporation of those regions. Despite Anglo-French guarantees of the integrity of rump Czechoslovakia, the Germans dismembered the Czechoslovak state in March 1939, in violation of the Munich agreement. Britain and France responded by guaranteeing the integrity of the Polish state. Hitler went on to negotiate a nonaggression pact with the Soviet Union. The German-Soviet Pact of August 1939, which secretly stated that Poland was to be partitioned between the two powers, enabled Germany to attack Poland without the fear of Soviet intervention.

Invasion and Partition of Poland

On September 1, 1939, Germany invaded Poland. To justify the action, Nazi propagandists falsely claimed that Poland had been planning, with its allies Great Britain and France, to encircle and dismember Germany and that Poles were persecuting ethnic Germans. The SS, in collusion with the German military, staged a phony Polish attack on a German radio station. Hitler then used this action to launch a “retaliatory” campaign against Poland.  

Fall of Warsaw

Poland mobilized late, and political considerations forced its army into a disadvantageous deployment. The Poles were also heavily outnumbered. Despite fighting tenaciously and inflicting serious casualties on the Germans, the Polish army was defeated within weeks. From East Prussia and Germany in the north and Silesia and Slovakia in the south, German units, with more than 2,000 tanks and over 1,000 planes, broke through Polish defenses along the border and advanced on Warsaw in a massive encirclement attack. After heavy shelling and bombing, Warsaw surrendered to the Germans on September 27, 1939. Britain and France, standing by their guarantee of Poland's border, had declared war on Germany on September 3, 1939. The Soviet Union invaded eastern Poland on September 17, 1939. The last resistance ended on October 6. The demarcation line for the partition of German- and Soviet-occupied Poland was along the Bug River.


In October 1939, Germany directly annexed former Polish territories along German's eastern border: West Prussia, Poznan, Upper Silesia, and the former Free City of Danzig. The remainder of German-occupied Poland (including the cities of Warsaw, Krakow, Radom, and Lublin) was organized as the so-called Generalgouvernement (General Government) under a civilian governor general, the Nazi Party lawyer Hans Frank.

Nazi Germany occupied the remainder of Poland when it invaded the Soviet Union in June 1941. Poland remained under German occupation until January 1945.

Discussion Questions

Critical Thinking Questions

  • Investigate the reasoning behind various choices by the Allies in response to German policy and military moves in the 1930s.
  • What factors might affect national responses to aggression?
  • What does war make possible?

Further Reading

Rossino, Alexander B. Hitler Strikes Poland: Blitzkrieg, Ideology, and Atrocity. Lawrence: University Press of Kansas, 2003.

Zaloga, Steve. Poland 1939: The Birth of Blitzkrieg. Westport, CT: Praeger, 2004.

Record, Jeffrey. The Specter of Munich: Reconsidering the Lessons of Appeasing Hitler. Washington, DC: Potomac Books, 2007.

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