The Bizone (German: [ˈbiːˌt͡soːnə] (listen)) or Bizonia was the combination of the American and the British occupation zones on 1 January 1947 during the occupation of Germany after World War II. With the addition of the French occupation zone on 1 August 1948 the entity became the Trizone (German: [ˈtʁiːˌt͡soːnə] (listen); sometimes jokingly called Trizonesia (German: Trizonesien, German pronunciation: [tʁit͡soˈneːzi̯ən] (listen))). Later, on 23 May 1949, the Trizone became the Federal Republic of Germany, commonly known as West Germany.