TURNING POINTS
Beyond Danzig: Why Hitler Invaded Poland in 1939
The September 1939 attack grew from Nazi expansionism, a calculated bargain with Stalin, and Hitler’s belief that Britain and France would not—or could not—stop him.
Germany’s invasion of Poland was not a limited dispute over Danzig. It was a planned war of conquest, enabled by a pact with Stalin and shaped by Hitler’s belief that the Western powers would not stop him.
At 4:45 a.m. on September 1, 1939, the German battleship <em>Schleswig-Holstein</em> fired on the Polish military depot at Westerplatte, near the Free City of Danzig. German forces entered Poland from the north, west, and south without a formal declaration of war. The attack began the European war that became World War II. [1][4][6]
Hitler publicly pointed to disputes over Danzig and the Polish Corridor. Those disputes mattered, but they were not the full purpose of the invasion. Nazi policy treated Poland as an obstacle to be destroyed and its land as part of a wider project of conquest in Eastern Europe. [1][2]
<h2>Danzig Was a Pretext for a Larger War</h2>
After World War I, Danzig—now Gdańsk—became a semi-autonomous Free City rather than part of Germany or Poland. The Polish Corridor gave Poland access to the Baltic Sea while separating East Prussia from the rest of Germany. Hitler demanded Danzig’s return and an extraterritorial road and rail connection across the corridor.
Polish leaders saw that accepting those demands could weaken their country’s sovereignty and invite further pressure. Poland refused. Germany and Poland had signed a 10-year non-aggression declaration in 1934, but Hitler publicly renounced it on April 28, 1939. [2]
For Hitler, Poland lay in the path of <em>Lebensraum</em>, or “living space,” the Nazi drive for expansion in Eastern Europe. Nazi rule in the region depended on conquest and the subjugation of existing populations. Danzig and the corridor gave Hitler useful grievances; the invasion aimed at the destruction of the Polish state. [1]
German authorities later annexed Danzig and large areas of western Poland into the Reich. Other occupied Polish territory was administered as the General Government. [6]
<h2>Appeasement Shaped Hitler’s Calculation</h2>
The invasion followed a series of German gains: the remilitarization of the Rhineland, the annexation of Austria, and the dismantling of Czechoslovakia. In March 1939, Germany occupied Bohemia and Moravia, violating the settlement reached at Munich only months earlier. The move showed that concessions over the Sudetenland had not satisfied Hitler. [3]
Britain then changed course. On March 31, Prime Minister Neville Chamberlain announced an Anglo-French guarantee of Polish independence. The pledge did not mean Britain and France could immediately save Poland from a German assault. It did mean that attacking Poland risked war with the Western powers. [3]
Hitler proceeded anyway. Earlier successes had encouraged him to believe Britain and France might retreat again. He also sought to remove the danger of Soviet intervention.
<h2>The Pact With Stalin</h2>
On August 23, 1939, Germany and the Soviet Union signed the Molotov-Ribbentrop Pact, named for Foreign Ministers Joachim von Ribbentrop and Vyacheslav Molotov. Publicly, it was a non-aggression agreement. Its secret protocol divided Eastern Europe into German and Soviet spheres of influence and provided for the partition of Poland. [1][5]
For Hitler, the agreement reduced the immediate risk of a two-front war. For Stalin, it opened the way for Soviet territorial gains. Their ideological conflict had not disappeared; the pact postponed it while leaving Poland exposed. [1][5]
On September 17, the Red Army entered eastern Poland. Soviet authorities claimed that the Polish state no longer existed, but the invasion followed the arrangement made with Berlin. Poland was partitioned between two neighboring powers. [1][5]
<h2>A Manufactured Excuse</h2>
On August 31, SS operatives staged an attack on a radio station at Gleiwitz near the Polish border and presented it as a Polish raid. The false-flag operation supplied propaganda for Germany’s claim that it was responding to Polish aggression. [1]
The next morning, Germany attacked. Its forces combined mechanized units and air power against Polish defenses while striking from several directions. [2][4]
Warsaw endured aerial bombardment and artillery fire before capitulating on September 28. Regular Polish resistance continued in places into early October and ended after the Battle of Kock on October 6. [4]
<h2>Britain and France Went to War</h2>
Britain and France demanded that Germany withdraw from Poland. Hitler ignored the ultimatum, and both countries declared war on Germany on September 3. [3]
The declarations did not prevent Poland’s defeat. But they ended the pattern of concessions that had marked the late 1930s and turned Germany’s assault on Poland into a wider European war.
Hitler invaded Poland because Nazi ideology called for conquest in the East, because Poland would not surrender its sovereignty under German pressure, and because the agreement with Stalin reduced the immediate military risk. He also believed Britain and France could be defied. Their declarations of war proved otherwise, though Poland bore the immediate cost of the decisions made in Berlin and Moscow.
<h2>Frequently Asked Questions</h2>
<h3>When did Germany invade Poland?</h3>
Germany invaded Poland on September 1, 1939. The attack began without a formal declaration of war, and the shelling of Westerplatte by the <em>Schleswig-Holstein</em> became one of its best-known opening actions. [1][6]
<h3>Why did Britain and France declare war on Germany?</h3>
Britain and France had guaranteed Polish independence after Germany occupied the rest of the Czech lands in March 1939. When Hitler refused to withdraw German forces from Poland, they declared war on September 3. [3]
<h3>What did the Molotov-Ribbentrop Pact have to do with the invasion?</h3>
The August 23 agreement reduced Hitler’s fear of immediate Soviet opposition and secretly set out a German-Soviet division of Poland. It gave Germany greater freedom to launch its attack while promising Soviet gains in Eastern Europe. [1][5]
<h3>Did the Soviet Union also invade Poland in 1939?</h3>
Yes. Soviet forces entered eastern Poland on September 17, 1939, in keeping with the secret protocol attached to the German-Soviet pact. [1][5]
TIMELINE
Key moments
Sources
- The Invasion of Poland — The National WWII Museum
- Invasion of Poland, Fall 1939 — United States Holocaust Memorial Museum
- Why the Invasion of Poland in 1939 Launched World War II — TIME
- Invasion of Poland (1939) — Encyclopaedia Britannica
- Soviet Union invades Poland — History.com
- RG 84: Poland — U.S. National Archives and Records Administration
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