Soviet invasion of Poland

Overview

The Soviet invasion of Poland was a military conflict by the Soviet Union without a formal declaration of war. On 17 September 1939, the Soviet Union invaded Poland from the east, 16 days after Nazi Germany invaded Poland from the west. Subsequent military operations lasted for the following 20 days and ended on 6 October 1939 with the two-way division and annexation of the entire territory of the Second Polish Republic by Nazi Germany and the Soviet Union. This division is sometimes called the Fourth Partition of Poland. The Soviet invasion of Poland was indirectly indicated in the "secret protocol" of the Molotov–Ribbentrop Pact signed on 23 August 1939, which divided Poland into "spheres of influence" of the two powers. German and Soviet cooperation in the invasion of Poland has been described as co-belligerence.

Overview adapted from Wikipedia, licensed under CC BY-SA 4.0.

Significance

The Soviet invasion of Poland on 17 September 1939 completed the strategic encirclement of the Second Polish Republic, which was already engaged against Nazi Germany's invasion from the west sixteen days earlier. Launched without a formal declaration of war, the Soviet operation was directly tied to the secret protocol of the Molotov–Ribbentrop Pact signed on 23 August 1939, which had divided Poland into predetermined spheres of influence between the two powers. Facing a combined Soviet force of 600,000–800,000 troops against a Polish force of approximately 20,000 in the east, organized Polish resistance collapsed within 20 days. By 6 October 1939, the entire territory of the Second Polish Republic had been partitioned and annexed between Nazi Germany and the Soviet Union — an outcome historians have characterized as the Fourth Partition of Poland. The German-Soviet co-belligerence that produced this result demonstrated the operational consequences of the Pact and eliminated Poland as an independent state for the duration of the war, fundamentally altering the strategic map of Eastern Europe at the outset of the conflict.

Forces & casualties

Commanders (3)