Little-known today, the German colonial empire in the Pacific began with Hanseatic League merchant ships and traders establishing footholds in the South Pacific beginning in the early 1800s. By the 1880s, Germany dominated the copra trade throughout the New Britain, Caroline, and Marshall Islands. Copra is the dried meat or kernel of the coconut, from which coconut oil is extracted. German commercial interests and, eventually, Kaiser Wilhelm noted the lack of interest among other European powers in large portions the central and western Pacific, staking claims to Western New Guinea and the adjacent Neu-Pomerania (New Britain) Archipelago, referred to Kaiser-Wilhelmsland. The Bismarck Archipelago and the Solomon Islands were soon added. With the end of the Spanish-American War came the termination of any ability on the part of Spain to rule its remaining colonies in the central Pacific, consisting of the Caroline Islands and the Mariana Islands, excluding Guam which had been ceded to the United States. Those remaining colonies were sold in 1899 to Germany for 25 million pesetas. Its newly acquired islands were merged into German New Guinea (Deutsch-Neuguinea). In 1906, Germany formally annexed the Marshall Islands into German New Guinea. To maintain the profitability of the copra trade and other commercial activity in German New Guinea, the German Government instituted a forced labor policy, requiring tribes to furnish four weeks of labor per person annually. Naturally, this policy led to significant unrest. With the outbreak of World War I in 1914, Australian troops quickly captured Kaiser-Wilhelmsland and the nearby islands. Soon thereafter, the Japanese Imperial Navy occupied the remaining portions of German New Guinea. These two military conquests were formally recognized after the end of hostilities, with the Territory of New Guinea (including the Bismarck Archipelago, the Solomon Islands, and Nauru) established as a League of Nations Mandate under Australian administration and the remaining islands becoming the South Pacific Mandate under Japanese administration.