The Russian revolution causes rebellion in Central Poland. Mass demonstrations in Warsaw are terminated by the imposition of the state of emergency.
Beginning of the First World War (01.08.1914). Russia allies itself with the Western powers in the war against the German Empire and Austria Hungary.
Battle of Tannenberg - the Russian army is destroyed by the German troops under guidance of Paul von Hindenburg and Erich Ludendorff.
Deportation to Russia - the Russian administration considers the Germans living in Poland as internal enemies. Whole German village communities are deported to Russia (Saratov). Most of them could return in 1918.
Downfall of the Russian Czar. The temporary Russian government recognizes the right of self-determination for Poland. Also the allies of the First World War promote a sovereign Polish state.
Abdication of William II. - Prussia becomes a republican Free State.
The Republic of Poland is proclaimed (11.11.1918). Jozef Pilsudski becomes the temporary head of state and receives dictatorial authority.
Contract of Versaille - Poland gains the majority of West Prussia, the "Danzig Corridor" and almost the whole province of Posen.
Polish Soviet war (1920-1921) about the border line between both states. Poland had not recognized the border line already fixed in 1919 that had followed the language border.
Peace of Riga - ends the Polish-Soviet war with a compromise that splits the disputed territories in Belarus and Ukraine between Poland and Soviet Russia. Two Polish Autonomous Districts within the Soviet Union were created: one in Belarus near Minsk, the other in Volhynia, 100 km west of Zhytomyr.
After violent arguments between Poles and Germans a commission of the League of Nations decides to divide the Upper Silesia - the partition of a district which is essentially a valuable economic unit. The Council awards the greater part of the Upper Silesian industrial district to Poland.
After the parliamentary elections president Pilsudski withdraws. Its successor Gabriel Narutowicz is murdered only a few days after assumption of office. New president becomes Stanislaw Wojciechowski.
Military putsch - Jozef Pilsudski seizes again power (12.05.1926). The political style becomes increasingly authoritarian and is characterized by restrictive minority politics.
In April Adolf Hitler cancels the Polish German no aggression treaty of 1934.
As a result there is an increased anti-German attitude in Poland. There are more and more acts of violence against the German fellow citizens.
At the beginning of the Second World War German settlers in Poland are brought to the Polish concentration camp Bereza Kartuska.
A supplementary protocol of the German Soviet no aggression treaty agreed upon between the dictators Adolf Hitler and Josef Stalin plans an allocation of Poland between the USSR and the German Reich.
The Second World War begins with the German attack on the Polish garrison on the Westerplatte near Danzig. A little later the Soviet Red Army occupies East Poland.
Polish counterattack against the German and Soviet armies. The largest battle during this campaign takes place near the Bzura river west of Warsaw from September 9 to September 18. The counterattack fails after an initial success.
The "Generalgouvernement Poland" is created from the remaining areas of Central Poland after West Prussia and Posen were integrated into the German Reich. The Polish population in the "Generalgouvernement" suffers substantial repressions.
The attack of Hitler on the USSR leads to the occupation of East Poland by the German Reich.
Warsaw Uprising - peak of the embittered resistance of Polish partisans and the Armia Krajowa (homeland army).
In July the Red Army crosses the Bug river toward the west. The German army is gradually pushed back.
12. January 1945 the Russian major offensive - the Soviet Red Army occupies all of Poland within a few days.
On 12. January the Nazi authorities still spread slogans to keep up. For propaganda reasons they prohibit the evacuation of the civilian population.
For the eastern part of the Warthegau permission for evacuation was given on 16. January for wives and children and on 18. January for the rest of the German inhabitants.
On 18. January the Red Army crossed the line Płock-Lodz-Cracow.
Yalta Conference - agreement over the Polish east border in favor of the USSR. Poland is to be compensated for it by German areas in the west and the north.
Stalin awarded Poland all the German territories in Pomerania, Silesia and Brandenburg east of the Oder-Neisse Line, plus the southern half of East Prussia.
May 1945 - the Soviet Red Army reaches Berlin and receives the unconditional surrender of Germany. Thus the war is terminated in Europe.
Agreement of Potsdam - the three Allied powers Great Britain, USSR and the USA specify new borders for Poland. The entire national territory shifts to the west up to the rivers Oder and Neisse. In the east Poland has to transfer large parts (including the city of Lemberg) to the USSR.
After the new definition of the Polish borders nearly three million Germans from the now Polish areas are expelled.
At the same time Polish people originating from East Poland are settled in the new West Polish areas.
In addition the restrictive minority politics of the communist regime forces thousands of just returned Jewish Nazi victims to leave Poland again for Israel and the USA.
By 1950 5 million Poles had been settled in what the Poles now called the Regained Territories.
Under the guidance of the Polish United Workers' Party (the communist party's official name) Poland becomes the "People's Republic of Poland".
Establishment of the "Warsaw Pact" for friendship and co-operation with the Soviet Union and other states of the Eastern Bloc.
The East contracts, substantially influenced by Chancellor Willy Brandt are meant to relax the relations between Poland and the Federal Republic of Germany by the acknowledgment of the inviolability of the existing borders.
Bottlenecks and repeated price increases release strike waves again and again. Strikes in Danzig spread to whole Poland. The independent trade union "Solidarnosz" is founded.
Head of state Jaruzelski places Poland under martial law and uses force of arms against factory hands and miners.
In the contract of the German Unity Germany recognizes obligatorily the west border of Poland following Oder and Neisse as international law.