The Czechoslovak National Assembly adopts the Constitution.

The First Czechoslovak Republic, often colloquially referred to as the First Republic, was the first Czechoslovak state that existed from 1918 to 1938, a union of ethnic Czechs and Slovaks. The country was commonly called Czechoslovakia a compound of Czech and Slovak; which gradually became the most widely used name for its successor states. It was composed of former territories of Austria-Hungary, inheriting different systems of administration from the formerly Austrian and Hungarian territories.

The Czechoslovak Constitution of 1920 was the second constitution of Czechoslovakia. Ratified after World War I, the constitution established Czechoslovakia as a democratic republic. It was adopted by the National Assembly on 29 February 1920 and replaced the provisional constitution adopted on 13 November 1918.

February 29 is a leap day —an intercalary date added periodically to create leap years in the Julian and Gregorian calendars. It is the 60th day of a leap year in both Julian and Gregorian calendars, and 306 days remain until the end of the leap year. It is the last day of February in leap years only. It is also the last day of meteorological winter in the Northern Hemisphere and the last day of meteorological summer in the Southern Hemisphere in leap years.