Topic summary
Invasion of Poland
Germany
Slovakia
Soviet Union
Poland- OKH:
Walther von Brauchitsch- Franz Halder
- Army Group North:
- Fedor von Bock
- Georg von Küchler
- Günther von Kluge
- Army Group South:
- Gerd von Rundstedt
- Johannes Blaskowitz
- Walter von Reichenau
- Wilhelm List
Ferdinand Čatloš- Luftwaffe:
- Albert Kesselring
- Alexander Löhr
- Red Army
Kliment Voroshilov- Mikhail Kovalev
- Semyon Timoshenko
- Total: 2,000,000+
- Nazi Germany:
- 66 divisions
- 6 brigades
- 9,000 guns
- 2,750 tanks
- 2,315 aircraft
- Slovak Republic:
- 3 divisions
Soviet Union:- 33+ divisions
- 11+ brigades
- 4,959 guns
- 4,736 tanks
- 3,300 aircraft
- Total: 59,000
- Nazi Germany:
- 16,343 killed
- 30,300 wounded
- 3,500 missing
- 236 tanks
- 800 vehicles
- 246 aircraft
- Slovak Republic:
- 37 killed
- 11 missing
- 114 wounded
- 2 aircraft
Soviet Union:- 1,475 killed
- 2,383 wounded
- or 5,327 casualties
- 43 tanks
- Total: ~874,700
- 66,000 killed
- 133,700 wounded
- ~690,000 captured
- 132 tanks and cars
- 327 aircraft
The invasion of Poland, also known as the September Campaign, Polish Campaign, and Polish Defensive War of 1939 (1 September – 6 October 1939), was a joint attack on the Republic of Poland by Nazi Germany, the Slovak Republic, and the Soviet Union, which marked the beginning of World War II. The invasion began on 1 September 1939 when Germany marched into Poland, preceded by the Danzig crisis and by the Molotov–Ribbentrop Pact between Germany and the Soviet Union, which was signed one week before and approved by the Supreme Soviet of the Soviet Union one day before the invasion. On 17 September the Soviet Union invaded as well, acting on a secret protocol of the pact, which assigned parts of Poland to them. The campaign ended on 6 October with Germany and the Soviet Union dividing the whole of Poland under the terms of the German–Soviet Frontier Treaty.
The aim of the invasion was to disestablish Poland as a sovereign country, with its citizens destined for extermination. German and Slovak forces invaded Poland from the north, south, and west the morning after the Gleiwitz incident. As the Wehrmacht advanced, Polish forces withdrew from their forward bases of operation close to the Germany–Poland border to more established defense lines to the east. After the mid-September Polish defeat in the Battle of the Bzura, the Germans gained an undisputed advantage. Polish forces then withdrew to the southeast where they prepared for a long defence of the Romanian Bridgehead and awaited expected support and relief from France and the United Kingdom. On 3 September, based on their alliance agreements with Poland, the United Kingdom and France declared war on Germany; in the end their aid to Poland was very limited. France invaded a small part of Germany in the Saar Offensive, and the Polish army was effectively defeated even before the could be transported to continental Europe.
On 17 September, the Soviet Red Army invaded Eastern Poland, the territory beyond the Curzon Line that fell into the Soviet "sphere of influence" according to the secret protocol of the Molotov–Ribbentrop Pact; this rendered the Polish plan of defence obsolete. Facing a second front, the Polish government concluded the defence of the Romanian Bridgehead was no longer feasible and ordered an emergency evacuation of all troops to neutral Romania. On 6 October, following the Polish defeat at the Battle of Kock, German and Soviet forces gained full control over Poland. The success of the invasion marked the end of the Second Polish Republic, though Poland never formally surrendered.
On 8 October, after an initial period of military administration, Germany directly annexed western Poland and the former Free City of Danzig and placed the remaining block of territory under the administration of the newly established General Government. The Soviet Union incorporated its newly acquired areas into its constituent Byelorussian and Ukrainianrepublics, and immediately started a campaign of Sovietization. In the aftermath of the invasion, a collective of underground resistance organizations formed the Polish Underground State within the territory of the former Polish state. Many of the military exiles who escaped Poland joined the Polish Armed Forces in the West, an armed force loyal to the Polish government-in-exile.