On 18 March 1931 France transferred the Tibesti Mountains from Niger (AOF) to Chad (AEF), thus completing what is now the Chad–Libya border.[1] On 7 January 1935 France and Italy signed a treaty which shifted the boundary southwards; the area between the two boundaries became known as the Aouzou Strip, however this agreement was never formally ratified by both parties.[2][9][4] During the North African Campaign of the Second World War Italy was defeated and its African colonies were occupied by the Allied powers, with Libya split into British and French zones of occupation.[4] Libya was later granted full independence on 2 December 1951.