Polish government-in-exile in the context of "Flight and expulsion of Germans (1944–50)"

The history of Poland from 1945 to 1989 spans the period of Marxist–Leninist regime in Poland after the end of World War II. These years, while featuring general industrialization, urbanization and many improvements in the standard of living, were marred by early Stalinist repressions, social unrest, political strife and severe economic difficulties.Near the end of World War II, the advancing Soviet Red Army, along with the Polish Armed Forces in the East, pushed out the Nazi German forces from occupied Poland. In February 1945, the Yalta Conference sanctioned the formation of a provisional government of Poland from a compromise coalition, until postwar elections. Joseph Stalin, the leader of the Soviet Union, manipulated the implementation of that ruling. A practically communist-controlled Provisional Government of National Unity was formed in Warsaw by ignoring the Polish government-in-exile based in London since 1940.

During the subsequent Potsdam Conference in July–August 1945, the three major Allies ratified a massive westerly shift of Poland's borders and approved its new territory between the Oder–Neisse line and the Curzon Line. The area of Poland was reduced in comparison to its pre-World War II extent and geographically resembled that of the medieval early Piast dynasty era. Following the destruction of the Polish-Jewish population in the Holocaust, the flight and expulsion of Germans in the west, resettlement of Ukrainians in the east, and the expulsion and resettlement of Poles from the Eastern Borderlands (Kresy), Poland became for the first time in its history an ethnically homogeneous nation-state without prominent minorities. The new government solidified its political power, while the Polish United Workers' Party (PZPR) under Bolesław Bierut gained firm control over the country, which would remain an independent state within the Soviet sphere of influence. The July Constitution was promulgated on 22 July 1952 and the country officially became the Polish People's Republic (PRL).

The Second Polish Republic, officially known at the time as the Republic of Poland, was a country in Central and Eastern Europe that existed between 7 October 1918 and 6 October 1939 after being established in the final stage of World War I. The Second Republic was taken over in 1939, after it was invaded by Nazi Germany, the Soviet Union, and the Slovak Republic, marking the beginning of the European theatre of the Second World War. The Polish government-in-exile was established in Paris and later London after the fall of France in 1940.

When, after several regional conflicts, most importantly the victorious Polish-Soviet war, the borders of the state were finalized in 1922, Poland's neighbours were Czechoslovakia, Germany, the Free City of Danzig, Lithuania, Latvia, Romania, and the Soviet Union. It had access to the Baltic Sea via a short strip of coastline known as the Polish Corridor on either side of the city of Gdynia. Between March and August 1939, Poland also shared a border with the then-Hungarian governorate of Subcarpathia. In 1938, the Second Republic was the sixth largest country in Europe. According to the 1921 census, the number of inhabitants was 25.7 million. By 1939, just before the outbreak of World War II, this had grown to an estimated 35.1 million. Almost a third of the population came from minority groups: 13.9% Ukrainians; 10% Ashkenazi Jews; 3.1% Belarusians; 2.3% Germans and 3.4% Czechs and Lithuanians. At the same time, a significant number of ethnic Poles lived outside the country's borders.

The Polish Armed Forces in the East (Polish: Polskie Siły Zbrojne na Wschodzie), also called Polish Army in the USSR, were the Polish military forces established in the Soviet Union during World War II.

Two armies were formed separately and at different times. Anders' Army, created in the second half of 1941, was loyal to the Polish government-in-exile. After Operation Barbarossa and the consequent Polish-Soviet Sikorski–Mayski agreement, an amnesty for Polish citizens in the Soviet Union was declared, which made the formation of Polish military units possible. In 1942, Anders' Army was evacuated to Iran and transferred to the command of the Western Allies. It became known as the Polish II Corps and went on to fight Nazi German forces in the Italian Campaign, including the Battle of Monte Cassino.

On 10 April 2010, a Tupolev Tu-154 aircraft operating Polish Air Force Flight PLF 101 crashed near the Russian city of Smolensk, killing all 96 people on board. Among the victims were the president of Poland, Lech Kaczyński, and his wife, Maria; the former president of Poland-in-exile, Ryszard Kaczorowski; the chief of the Polish General Staff and other senior Polish military officers; the president of the National Bank of Poland; Polish government officials; 18 members of the Polish parliament; senior members of the Polish clergy; and relatives of victims of the Katyn massacre. The group was arriving from Warsaw to attend an event commemorating the 70th anniversary of the massacre, which took place not far from Smolensk.

The pilots were attempting to land at Smolensk North Airport — a former military airbase — in fog, with visibility reduced to about 400 metres (about 400 yards). The aircraft descended far below the normal approach path until it struck trees, rolled, inverted and crashed into the ground, coming to rest in a wooded area a short distance from the runway.

The Polish People's Army (Polish: Ludowe Wojsko Polskie, pronounced [luˈdɔvɛ ˈvɔjskɔ ˈpɔlskʲɛ]; LWP) was the second formation of the Polish Armed Forces in the East during the latter stages of the Second World War (1943–1945), and subsequently the armed forces of the Polish communist state (1945–1989), which was formalized in 1952 as the Polish People's Republic.

The creation of communist-led Polish armed forces that were outside the command of the Polish government-in-exile was allowed and facilitated by Soviet leader Joseph Stalin, following efforts made in the early 1940s by Soviet-based Polish exiles Wanda Wasilewska and Zygmunt Berling.

The Provisional Government of National Unity (Polish: Tymczasowy Rząd Jedności Narodowej, TRJN) was a puppet government formed by the decree of the State National Council (Krajowa Rada Narodowa, KRN) on 28 June 1945 as a result of reshuffling the Soviet-backed Provisional Government of the Republic of Poland established by the Polish Workers' Party (Polska Partia Robotnicza, PPR) through inclusion of politicians from the close political sphere of Stanisław Mikołajczyk, the former prime minister of the Polish government-in-exile based in London. Inclusion of the latter group provided an excuse for the Western allies to approve tacitly the fait accompli of Poland becoming part of the Soviet sphere of influence, and to legitimise the Warsaw government while withdrawing their recognition of the Polish government-in-exile. The puppet government became known as the "Lublin Committee" or the "Lublin Poles" or the "Lublin Government", and it garnered the recognition of all Allied governments at the time.