The May Coup was a coup d'état carried out in Poland by Marshal Józef Piłsudski from 12 to 14 May 1926. The attack of Piłsudski's supporters on government forces resulted in an overthrow of the democratically-elected government of President Stanisław Wojciechowski and Prime Minister Wincenty Witos and caused hundreds of fatalities. A new government was installed, headed by Kazimierz Bartel. Ignacy Mościcki became president. Piłsudski remained the dominant politician in Poland until his death in 1935.

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 6 October 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 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.