# Soviet invasion of Poland (1939)

URL: https://poland-history.com/timeline/1939-soviet-invasion-of-poland
Location: Eastern Poland
Categories: battle, main-event

On 17 September 1939 the Red Army invaded eastern Poland under the secret protocol of the Molotov–Ribbentrop Pact. Within the broader World War II period: Invaded by Germany and the Soviet Union, Poland suffered brutal occupation and the Holocaust, while its underground state and armed forces fought on every front of the war. At this point in the timeline (17 September 1939), the governing authority was Ignacy Mościcki (President of Poland). Chemist and inventor elected with Piłsudski's backing; interned in Romania in 1939 he transferred office to Raczkiewicz. Soviet invasion of Poland mattered because it changed the military or territorial balance and influenced the political choices that followed. The event is placed here so readers can follow it alongside changes in government, warfare, society, religion and culture across Polish history.

## Why it matters
Soviet invasion of Poland mattered because it changed the military or territorial balance and influenced the political choices that followed.

Ruler at the time: [Władysław Raczkiewicz](https://poland-history.com/rulers/wladyslaw-raczkiewicz)

## Sources
- [Wikipedia — Soviet invasion of Poland](https://en.wikipedia.org/wiki/Soviet_invasion_of_Poland)
- [Encyclopaedia Britannica topic lookup — Soviet invasion of Poland](https://www.britannica.com/search?query=Soviet+invasion+of+Poland)
- [Wikipedia — History of Poland (1939–1945) (period overview)](https://en.wikipedia.org/wiki/History_of_Poland_(1939%E2%80%931945))