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.