The Second Polish Republic adopts the March Constitution.

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 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.

The Second Polish Republic adopted the March Constitution on 17 March 1921, after ousting the occupation of the German/Prussian forces in the 1918 Greater Poland Uprising, and avoiding conquest by the Soviets in the 1920 Polish-Soviet War. The Constitution, based on the Constitution of the Third French Republic, was regarded as very democratic. Among others, it expressly ruled out discrimination on racial or religious grounds. It also abolished all royal titles and state privileges, and banned the use of blazons.