What’s New
8th April 2026
The Invasion of Poland timeline has been further expanded with four new photographs and two additional contemporary quotations, providing greater visual and first-hand context for key stages of the campaign. Entries for 18th to 22nd September 1939 have also been thoroughly revised and expanded, continuing the detailed reworking of the final phase of the campaign.
20th March 2026
The
Invasion of Poland timeline has been significantly revised once again, with the entries for 14th to the 17th September 1939 thoroughly overhauled to improve coverage of the final phase of the campaign.
A new campaign map has also been added for 17th September, illustrating the Soviet invasion of Poland and the widening collapse of Polish resistance from both east and west.
3rd March 2026
The Eastern Europe section now features a dedicated overview page, providing a central hub for the major campaigns and timelines across the Eastern European theatre.
Following recent work to the
Invasion of Poland timeline, significant updates have also been applied to the period
9th–13th September 1939, expanding coverage of key operations and developments during
this critical phase of the campaign.
Weapons of War
The T-26 was the most numerous tank in Soviet service at the outbreak of the Second World War and formed the backbone of the Red Army's armoured forces throughout the 1930s. Derived from the British Vickers 6-Ton design, it was progressively improved into a capable light tank armed with a powerful 45 mm gun and intended to support infantry formations during offensive operations.
Operated by a three-man crew, the T-26 combined effective firepower with relatively simple construction, allowing it to be produced in large numbers. Armour protection ranged from 15 to 25 mm depending on the model, while numerous specialised variants were developed, including flamethrower tanks, artillery tractors, bridge-layers, and command vehicles. More than 10,000 examples were built, making it one of the most widely produced tanks of the interwar period.
The T-26 saw action in the Spanish Civil War, at Khalkhin Gol, during the Winter War, and in the early battles against Germany in 1941. Although increasingly vulnerable to modern anti-tank weapons, it remained a significant component of Soviet armoured forces during the first year of Operation Barbarossa. Eventually replaced by newer designs such as the T-34, the T-26 nevertheless played a crucial role in the development of Soviet armoured warfare.
Timeline Highlights
1st September 1939
At 4:45am, Fall Weiss (Case White), the German Invasion of Poland begins and 2 minutes later at 4:47am the opening shots of World War 2 are fired by the German Battleship Schleswig-Holstein which had taken up a position in Danzig Bay opposite the Polish fort at Westerplatte. She opened up with a full broadside by her 11-inch guns at point blank range against the fort. German marines then attacked the Polish outposts, but were bloodily repulsed. At 7:40am the Schleswig-Holstein once again opened a barrage against the fort for about an hour, before a second attack by the marines was launched around 8:35am, which was also repulsed by the Poles.
3rd September 1939
Britain issues a final ultimatum to Germany at 9am, giving the Germans until 11am to agree to withdraw their troops from Poland. Just after the deadline a German response is received in the form of an 11 page document, which confirms their refusal to withdraw from Poland. At 11:15am Prime Minister, Neville Chamberlain announces that ‘no such undertaking has been received’ from Germany to withdraw their forces and he therefore declares that ‘Britain is now at war with Germany’. The declaration also commits Australia and New Zealand to the war, having been agreed in advance with their governments. Similarly France also declares war on Germany at 5pm following the expiry of its own ultimatum.
17th September 1939
With Poland already significantly weakened by the German invasion, the Soviet Union executes the secret clauses of the Molotov–Ribbentrop Pact, signed the previous month, which agreed the division of Poland between Nazi Germany and the Soviet Union, and begin an invasion from the east. Declaring that Poland no longer exists as an independent state and under the pretext of protecting the Byelorussian and Ukrainian populations living in Poland, two Soviet Fronts, Byelorussian in the north and the Ukrainian in the south, cross the frontier into Poland. The Soviet forces, numbering around 600,000 troops, 4,736 tanks, and 3,300 aircraft, encounter little resistance, as the Polish Army in the east consists mainly of border guards with very little artillery or air support.
27th September 1939
At 12pm a cease fire is agreed between German and Polish forces in Warsaw and at 2pm the city officially surrenders to the Wehrmacht. During the siege 18,000 civilians were killed and approximately 50% of the city is heavily damaged.
Gestapo–NKVD meeting in Brześć initiates the coordination of prisoner transfers and joint security operations between Nazi Germany and the Soviet Union. This marks the beginning of formal collaboration in managing occupied Polish territories. Further meetings are planned for October and November to oversee the reorganization of these areas and the handling of civilian populations.
5th October 1939
Adolf Hitler takes the salutes of the German Army during the ‘Siegesparade’ (Parade of Victory) through Warsaw.
Under mounting pressure from stronger German forces, supported by an unopposed Luftwaffe, Polish defences begin to crumble in the Battle of Kock, with German units breaking through several positions. Despite fierce resistance, Polish troops, running low on ammunition and food, initiate an organised withdrawal. General Kleeberg, recognising that continued resistance is unsustainable, begins surrender negotiations with the Germans.
Latvia having seen Estonia sign a ‘mutual assistance’ treaty with the Soviet Union and with no other options, sends its Foreign Minister Vilhelms Munters to Moscow to sign its own ‘mutual assistance’ Treaty with the Soviets allowing them to establish military bases in Latvia at Libau and Windau.
26th November 1939
The Red Army stages a false flag attack, shelling the town of Mainila on the Soviet side of the border. They accuse Finland of being responsible for the incident, claiming the Finns fired seven shells, killing four Red Army Soldiers.
1st December 1939
The Soviet Union officially establishes the Finnish Democratic Republic, a puppet government led by Finnish communist Otto Wille Kuusinen, in the town of Terijoki, which immediately accedes to the Soviet demands. The Soviet Union broadcasts propaganda messages claiming this government, which is intended as a Soviet-friendly alternative to the legitimate Finnish government, has the support of the Finnish people. This was an attempt to undermine the Finnish government and justify the invasion.
In Central Finland, the Soviet 163rd Rifle Division and an independent tank brigade having crossed the border at Juntusranta, while the 44th Rifle Division crossed at Raate, force the defending Finnish forces of about battalion strength, to conduct a fighting retreat towards the village of Suomussalmi.
7th January 1940
Finnish forces complete the destruction of the Soviet 44th Rifle Division along the Raate Road, as its remaining elements are forced to surrender, having been surrounded without supplies since the 1st January. In what became known as the Raate Road Massacre, many Red Army soldiers froze to death near the road, lacking adequate winter equipment and being unable to move off-road due to the Finnish ski troops controlling the surrounding countryside.
23rd February 1940
The Soviet Union announces its final conditions for peace with Finland. These included ceding a significant amount of territory in Karelia, including the city of Viipuri. Additionally, areas around Salla were also demanded, along with a thirty-year lease for a naval base on the Hanko Peninsula and various islands in the Gulf of Finland.
