The Second Polish Republic, at the time officially known as the Republic of Poland, was a country in Central and Eastern Europe that existed between 7 October 1918 and 30 September 1939. The state was established in the final stage of World War I. The Second Republic ceased to exist in 1939, after Poland was invaded by 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 to replace the Second Republic in the war.
When, after several regional conflicts, most importantly the victorious Polish-Soviet war, the borders of the state were finalised 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 27.2 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% Ruthenians; 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 Second Republic maintained moderate economic development. The cultural hubs of interwar Poland Warsaw, Kraków, Poznań, Wilno, and Lwów became major European cities and the sites of internationally acclaimed universities and other institutions of higher education. Although Polish Jews were some of the biggest supporters of Piłsudski, even after he returned to politics and consolidated power in 1926, in the 1930s, the Republic begun to openly discriminate against its Jewish (and to a lesser extent its Ukrainian) citizens, restricting Jewish entry into professions and placing limitations on Jewish businesses.