The exact origins of the Nauruans are unclear since their language does not resemble any other in the Pacific. The island was annexed by Germany in 1888. Its phosphate deposits began to be mined early in the 20th century by a German-British consortium. Nauru was occupied by Australian forces in World War I and subsequently became a League of Nations mandate. After the Second World War - and a brutal occupation by Japan - Nauru became a UN trust territory. It achieved independence in 1968 and joined the UN in 1999 as the world's smallest independent republic.