On This Day: Soviet Union invades Poland after Nazis at start of WWII

During WWII, Soviet Union would not hold gains in Poland for long, with the Nazis invading a few years later, kicking off the Eastern Front, one of the largest and most brutal conflicts in history

 Russian cavalry and infantry entering the Polish city of Wilno (Vilnius) after joint German-Russian aggression against Poland. (photo credit: Wikimedia Commons)
Russian cavalry and infantry entering the Polish city of Wilno (Vilnius) after joint German-Russian aggression against Poland.
(photo credit: Wikimedia Commons)

September 17, 2021 marks 82 years since the Soviet invasion of Poland, which followed the Nazi invasion 16 days prior which is widely credited as kicking off World War II, which remains the deadliest conflict in human history.

The background to the invasion is well known, but at the same time incredibly complex. 

The Soviets had fought a recent war with Poland in 1920, following the end of World War I. However, that war ended with the Soviets suing for peace after a decisive Polish victory at the Battle of Warsaw, regarded by some as among the most important battles in world history as it decisively stopped the Westward expansion of Communism.

Following this, Joseph Stalin took power in the Soviet Union, and eventually signed a non-aggression pact in the form of the Molotov-Ribbentrop with Nazi Germany.

This deal was important, as it essentially allowed for Poland to be divided between Germany and the Soviet Union.

The invasion as a whole lasted a little over a month, terminating on October 6. The Germans and Soviets, along with their Slovak allies, altogether had over 2 million soldiers, over double the number of forces the Polish could muster. The war was a disaster for Poland as, despite the best efforts of many of their soldiers, the country crumbled to the invaders. 

 Soviet cavalry on parade in Lviv, after the city's surrender to the Red Army during 1939 Soviet invasion of Poland. The city, then known as Lwów, was annexed by the Soviet Union and today is part of Ukraine. (credit: Wikimedia Commons)
Soviet cavalry on parade in Lviv, after the city's surrender to the Red Army during 1939 Soviet invasion of Poland. The city, then known as Lwów, was annexed by the Soviet Union and today is part of Ukraine. (credit: Wikimedia Commons)

This rapid conquest set the stage for World War II, as soon Germany, having just achieved near-total dominance over central Europe, would turn its attention to the West, taking on France and the United Kingdom shortly. 

The Soviet Union would not hold on to these gains for long, however. Just a few years later, the Nazis launched Operation Barbarossa and began invading Soviet territory. This saw them rapidly seize control of the rest of Poland and into Ukraine and the Baltics before entering Russia properly.

The Eastern Front of World War II remains one of, if not the largest and most brutal conflict in human history, resulting in around 30 million deaths, widespread atrocities and the largest battles ever waged.