The Australian Naval and Military Expeditionary Force (AN&amp;MEF) occupied German New Guinea in 1914, following the outbreak of World War I. After the war's end, Bougainville and the other occupied territories were named as a League of Nations mandate, which Australia administered as the Territory of New Guinea. During World War II, the Japanese invaded and occupied Bougainville in order to support their operations elsewhere in the Pacific. The subsequent Allied campaign to reclaim the islands resulted in heavy casualties and the eventual restoration of Australian control in 1945.