After World War I and fall of Austria-Hungary the region of Cieszyn Silesia including the territory of Teschen political district became disputed land between Czechoslovakia and Poland. This led to Polish–Czechoslovak War and the division of the region and district on 28 July 1920, by a decision of the Spa Conference. The part of Teschen district that was found within Czechoslovakia was superseded by Český Těšín District whereas the other part found in Poland was replaced by Cieszyn County, that was enlarged by municipalities of Freistadt and Bielitz districts.