September 1, 1939: The Invasion of Poland

The invasion of Poland was the trigger for World War II in Europe and signified the beginning of an era in which tens of millions of people would die.

Mar 18, 2024By Greg Beyer, BA History & Linguistics, Journalism Diploma
invasion of poland


September 1, 1939, was the beginning of a new era. For six long years, Europe would be thrown into a maelstrom of chaos and destruction as the Germans and their allies expanded the Third Reich, humbling nations before them and subjecting the continent to the crushing authoritarian jackboot of Nazism.


Tens of millions of people would die, not just on the frontlines, but from mass executions and genocide as the Nazis stamped their rule over Europe.


Poland was the first to feel this onslaught.


The Buildup to the Invasion of Poland

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Map of Poland on the eve of the Second World War. Source: Saltaire Collection


Hitler came to power in 1933, and for the 12 years of Nazi rule in Germany, the country followed an irredentist policy, reforming the glory of the Second Reich by annexing neighboring territories in its bid to rebuild an empire that was destroyed by the terms of the Treaty of Versailles, which ended the First World War.


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Annexation of neighboring territories was done under the justification of uniting German speakers into one country. Ethnic Germans living in Poland, however, formed a small minority of the country’s population, and instead, the Nazis claimed that the ethnic Germans living in Poland were subjected to persecution.


Whatever the truth of the matter, many German citizens in Poland were in favor of reunification with Germany. In the west of Poland, the Polish Corridor was land that had been taken away from Germany as a result of the Treaty of Versailles, and it separated Germany from the Free City of Danzig (today Gdańsk), where Germans formed a majority.


Danzig was an independent city-state formed in 1920 and was under the protection of the League of Nations, with special rights given to Poland as it was the only port in the Polish Corridor.


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The flag of the Second Polish Republic. Source: Wikimedia Commons


Germany began making demands of Poland on the subject of Danzig. Hitler wanted to link German territory with Danzig, and he proposed the construction of an extraterritorial highway between Germany, through Polish territory, and into Danzig and East Prussia, which was a German exclave. The Polish refused, believing that any concessions they made would weaken their position and give the Germans increased power over their nation.


Fearing the growing power of a belligerent Germany, Poland signed a military alliance with France and the United Kingdom in March 1939, hoping that it would deter Hitler from attempting any military action.


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German soldiers in 1939. Source: Store Norske Leksikon


Despite the political justifications and actions, Hitler viewed Poland and the Polish people with absolute contempt. In 1930, he wrote that the Poles and the Czechs were “rabble not worth a penny more than the inhabitants of Sudan or India.” He also stated privately that the invasion of Poland was for the purposes of Lebensraum and that Danzig was not an important issue.


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Polish soldiers in 1939. Source: Wikimedia Commons


In the months preceding the invasion, the German government began accusing the Polish government of conducting ethnic cleansing against Germans in Poland. This was part of Operation Himmler, a concerted propaganda effort to discredit Poland in the eyes of the local and international community.


On the night of August 31, the Germans carried out a series of false flag incidents along the Polish border, including the infamous Gleiwitz Incident, in which SS operatives dressed as Poles, seized the Gleiwitz radio station on German territory, and broadcast anti-German messages.


The following day, Poland was invaded.


The Invasion of Poland

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German soldiers pulling down a Polish border crossing during the initial stages of the invasion of Poland (colorized). Source: Wikimedia Commons


As dawn broke on September 1, 1939, Germany launched a surprise invasion of Poland. The main thrusts came from German-held East Prussia in the north, Silesia and Slovakia in the southwest, and from the northwest. With much of Poland’s army on the German border expecting an attack directly from the west, the Polish were caught completely off guard, and these armies were encircled.


From the very beginning, the Polish were overwhelmed on all fronts and in every department. Theoretically, they had one million men to resist the invasion, a not insubstantial number, but the Germans had mustered more than 60 divisions – over one and a half million with hundreds of thousands more to follow, supported by 2,000 tanks, 900 bombers, and 400 fighter planes. The Poles planned to hold up the German armies in the west in order to buy time for the UK and France to mobilize and send troops to aid their ally. Polish hopes, however, were dashed.


The UK and France declared war on Germany on September 3, but neither of these countries sent troops to aid the Poles, and to make matters worse, the Soviets opened another front and invaded Poland from the east.


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People looking at DC newspapers on Sept. 1, 1939. Source: Library of Congress


In the first days of the invasion, German propaganda claimed that the Polish Air Force had been destroyed on the ground. This was, unsurprisingly, a lie. The Poles had been caught unaware, mainly due to the direction of the German invasion and not simply the fact that it happened. The Polish had spread their air force out in expectation of conflict and were able to launch a spirited defense in the air.


The Polish, however, were outnumbered and were using vastly inferior aircraft. Polish pilots were well-trained, but it was not enough, and the Germans achieved air superiority within a very short period of time. This development would give the Germans the space to employ their Bewegungskrieg (mobile war), an extremely fast and effective use of military power that combined various elements, all in support of each other, to provide an overwhelming punch through the enemy defenses. This type of warfare became more commonly known as Blitzkrieg (lightning war).


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A Polish girl mourns the loss of her older sister, killed by a German air raid on September 13, 1939. Source: Julien Bryan, Wikimedia Commons


This new kind of warfare upset the plans not just of Poland but also the Allied intentions concerning Poland. France and the UK had declared war, but they felt that a few more months of military buildup were necessary before they could send any effective military relief to the beleaguered Poles. They expected the Poles to be able to hold out until then.


As for the speed of the German campaign, it shocked everybody involved. Even the Germans were impressed with the efficacy of their new doctrine. In the first week, the Poles fell back significantly under the onslaught. They abandoned the Polish Corridor, Greater Poland, and Polish Upper Silesia. Meanwhile, Warsaw had been suffering aerial bombardments since the beginning of the war.


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German soldiers guarding a group of Jews in Sanok, Poland, September 1939. Source: Wikimedia Commons


The most significant battle during this period of the war was the Battle of Bzura, which lasted from September 9 to September 19. The German 8th Army had advanced rapidly eastwards and was directly west of Warsaw. With the rapid advance, the 8th Army’s flanks were open, and the Polish seized the opportunity to counterattack. They achieved temporary success but were finally overwhelmed and defeated in large part due to the uncontested superiority of the Luftwaffe.


On September 17, the Soviets invaded Poland from the east. This move was completely unexpected by everyone except the Germans and the Soviets themselves, who had created the plan to do so when they signed the non-aggression pact in late August 1939.


By the time of the Soviet invasion, the Polish forces had already been fragmented and operated without coordination. The day after the Soviets launched their invasion, the Polish government fled the country.


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German troops marching through Warsaw, September 1939. Source: National Archives US


Polish troops were also ordered to flee the country and reorganize in France. They were also ordered to fall back from the Soviet advance and not engage the enemy. It was quite clear that the war was completely lost, and the Polish government tried to save what they could of the armed forces. Nevertheless, the fighting continued.


Just west of Warsaw, the city of Lwów (today Lviv) fell on September 22. Warsaw held out for a few days longer, with Polish units completely surrounded, offering a resilient defense. The battle, however, was a foregone conclusion, and the city officially surrendered on October 28.


Various pockets of Polish troops held out for a few days. The last battle of the invasion was the Battle of Kock, which took place between Lublin and Warsaw from October 2 to October 5. The operation was finally concluded on October 6.


As per the agreement between the Germans and the Soviets, Poland was split in two along the Bug River, with the western half being annexed by Germany and the eastern half being annexed by the Soviet Union.



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Part of the Warsaw Ghetto. Source: Wikimedia Commons


Over 100,000 Polish soldiers managed to escape capture. They were welcomed by the British and the French and continued the fight against the Germans throughout the rest of the war. Of particular note was the high number of Polish pilots who flew combat actions against the Germans during the Battle of Britain.


Meanwhile, the German occupation of Poland was utterly brutal. The Warsaw Ghetto was created, and hundreds of thousands of Jews were interned there. From this junction, Jewish people were transported en masse to concentration camps and extermination camps that were built throughout Polish territory by the Nazis.


Of the 3.3 million Jews living in Poland before the war, only 380,000 survived.


The ethnic Poles were also subjected to brutality on an unprecedented scale, with millions being killed during the occupation. Polish resistance continued throughout the occupation, and small groups of resistance members operated over the whole country, striking at targets of opportunity and harassing the Germans till the very end when they were driven out by the Soviets.


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A 9-year-old boy, Ryszard Pajewski, sits in the ruins of Warsaw. Photograph by Julien Bryan. Source: Wikimedia Commons


The invasion of Poland was a sad lesson for the Allied powers. They watched helplessly as Poland was struck with the power of German military might and doctrine. Such a speedy campaign had never been seen before. Seven months later, the French suffered the same fate as the Poles and succumbed to the same German tactics.


Fueled by faith in their ideology, revolutionary tactics and strategy, and copious amounts of drugs, the Nazi armies seemed unstoppable.

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By Greg BeyerBA History & Linguistics, Journalism DiplomaGreg specializes in African History. He holds a BA in History & Linguistics and a Journalism Diploma from the University of Cape Town. A former English teacher, he now excels in academic writing and pursues his passion for art through drawing and painting in his free time.