The Second Polish Republic, officially known at the time as the Republic of Poland, was the Polish state 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 on the eve of its twenty-first anniversary, 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 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 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 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 Second Republic leader Józef Piłsudski, even after he returned to politics and staged a coup in 1926, after his death in 1935 the Pilsudskites ruling the Republic began to openly discriminate against its Jewish (and, to a lesser extent, its Ukrainian and Belarusian) citizens, restricting Jewish entry into professions and placing limitations on Jewish businesses.
The official name of the state was the Republic of Poland. In the Polish language, it was referred to as Rzeczpospolita Polska (abbr. RP), with the term Rzeczpospolita being a traditional name for the republic when referring to various Polish states, including the Polish–Lithuanian Commonwealth (considered to be the First Polish Republic, Pierwsza Rzeczpospolita), and later, the current Third Polish Republic. In other regionally-used official languages, the state was referred to as: Republik Polen in German, Польська Республіка (transcription: Polʹsʹka Respublika) in Ukrainian, Польская Рэспубліка (transcription: Poĺskaja Respublika) in Belarusian, and Lenkijos Respublika, in Lithuanian.
Between 14 November 1918 and 13 March 1919, the state was referred to in Polish as Republika Polska, instead of Rzeczpospolita Polska. Both terms mean the Republic; however, republika is a general term, while Rzeczpospolita traditionally refers exclusively to the Polish states. Additionally, between 8 November 1918 and 16 August 1919, the Journal of Laws of the State of Poland referred to the country as the State of Poland (Polish: Państwo Polskie).
Following the end of the Second World War, and the establishment of the later states of the Polish People's Republic and the Third Polish Republic, the historical state is referred to as the Second Polish Republic. In the Polish language, the country is traditionally referred to as II Rzeczpospolita (Druga Rzeczpospolita), which means the Second Republic.
After more than a century of partitions between the Austrian, the Prussian, and the Russian imperial powers, Poland re-emerged as a sovereign state at the end of the First World War in Europe in 1917–1918. The victorious Allies of the First World War confirmed the rebirth of Poland in the Treaty of Versailles of June 1919. It was one of the great stories of the 1919 Paris Peace Conference. Poland solidified its independence in a series of border wars fought by the newly formed Polish Army from 1918 to 1921. The extent of the eastern half of the interwar territory of Poland was settled diplomatically in 1922 and internationally recognised by the League of Nations.
Over the course of World War I (1914–1918), the German Empire gradually dominated the Eastern Front as the Imperial Russian Army fell back. German and Austro-Hungarian armies seized the Russian-ruled part of what became Poland. In a failed attempt to resolve the Polish question as quickly as possible, Berlin set up the puppet Kingdom of Poland on 14 January 1917, with a governing Provisional Council of State and (from 15 October 1917) a Regency Council (Rada Regencyjna Królestwa Polskiego). The Council administered the country under German auspices (see also Mitteleuropa), pending the election of a king. More than a month before Germany surrendered on 11 November 1918 and the war ended, the Regency Council had dissolved the Provisional Council of State and announced its intention to restore Polish independence (7 October 1918). With the notable exception of the Marxist-oriented Social Democratic Party of the Kingdom of Poland and Lithuania (SDKPiL), most Polish political parties supported this move. On 23 October, the Regency Council appointed a new government under Józef Świeżyński and began conscription into the Polish Army.
In 1918–1919, over 100 workers' councils sprang up on Polish territories; on 5 November 1918, in Lublin, the first Soviet of Delegates was established. On 6 November, socialists proclaimed the Republic of Tarnobrzeg at Tarnobrzeg in the Austrian Galicia. The same day, the Socialist, Ignacy Daszyński, set up a Provisional People's Government of the Republic of Poland (Tymczasowy Rząd Ludowy Republiki Polskiej) in Lublin. On Sunday, 10 November at 7 a.m., Józef Piłsudski, newly freed from 16 months in a German prison in Magdeburg, returned by train to Warsaw. Piłsudski, together with Colonel Kazimierz Sosnkowski, was greeted at Warsaw's railway station by Regent Zdzisław Lubomirski and by Colonel Adam Koc. The next day, due to his popularity and support from most political parties, the Regency Council appointed Piłsudski as Commander in Chief of the Polish Armed Forces. On 14 November, the Council dissolved itself and transferred all its authority to Piłsudski as Chief of State (Naczelnik Państwa). After consultation with Piłsudski, Daszyński's government dissolved itself and a new government was formed under Jędrzej Moraczewski. In 1918, the Kingdom of Italy became the first country in Europe to recognise Poland's renewed sovereignty.
Centres of government that formed at that time in Galicia (formerly Austrian-ruled southern Poland) included the National Council of the Principality of Cieszyn (established in November 1918), the Republic of Zakopane and the Polish Liquidation Committee (28 October). Soon afterward, the Polish–Ukrainian War broke out in Lwów (1 November 1918) between forces of the Military Committee of Ukrainians and the Polish irregular units made up of students known as the Lwów Eaglets, who were later supported by the Polish Army (see Battle of Lwów (1918), Battle of Przemyśl (1918)). Meanwhile, in western Poland, another war of national liberation began under the banner of the Greater Poland uprising (1918–1919). In January 1919, Czechoslovak forces attacked Polish units in the area of Trans-Olza (see Polish–Czechoslovak War). Soon afterwards, the Polish–Lithuanian War (ca 1919–1920) began, and, in August 1919, Polish-speaking residents of Upper Silesia initiated a series of three Silesian Uprisings. The most critical military conflict of that period, however, the Polish–Soviet War (1919–1921), ended in a decisive Polish victory.
The Second Polish Republic was a parliamentary democracy from 1919 (see Small Constitution of 1919) to 1926, with the President having limited powers. The Parliament elected him, and he could appoint the Prime Minister as well as the government with the Sejm's (lower house's) approval, but he could only dissolve the Sejm with the Senate's consent. Moreover, his power to pass decrees was limited by the requirement that the Prime Minister and the appropriate other Minister had to verify his decrees with their signatures. Poland was one of the first countries in the world to recognise women's suffrage. Women in Poland were granted the right to vote on 28 November 1918 by a decree of General Józef Piłsudski.