Kaiser-Wilhelmsland ("Emperor William's Land") formed part of German New Guinea (), the South Pacific protectorate of the German Empire. Named in honour of Wilhelm I, who reigned as German Emperor () from 1871 to 1888, it included the northern part of present-day Papua New Guinea. From 1884 until 1920 the territory was a protectorate () of the German Empire. Kaiser-Wilhelmsland, the Bismarck Archipelago (including New Mecklenburg and New Pomerania), the northern Solomon Islands, the Caroline Islands, Palau, Nauru, the Northern Mariana Islands, and the Marshall Islands comprised German New Guinea. Most of the German settlers in Kaiser-Wilhelmsland worked as plantation owners, miners, or government functionaries; the number of European settlers, including non-Germans, was never very high. In 1885, Lutheran and Catholic congregations sent clergy to establish missions; they experienced moderate, but very slow, success with the indigenous peoples. Missionaries and plantation owners alike were limited by tropical diseases and by travel and communication barriers. The Germans never fully explored the protectorate, though in 1914 the Imperial German Government mounted an expedition to explore and map the interior. Lutheran missionaries were frequently the first Europeans to explore the interior and to examine the different fauna and flora. Following the outbreak of World War I in July 1914, Australian troops quickly overran the German protectorate (September to November, 1914) and it came under Australian military administration. In accordance with the settlements ending World War I, from 1920 the Commonwealth of Australia, a British dominion, administered Kaiser-Wilhelmsland as part of the Territory of New Guinea, a League of Nations mandate. History The coastline of the northern and eastern portions of New Guinea had been charted by navigators in the early 17th century, and the visible mountain ranges named by British admiralty navigators later in the century. Most German surveying efforts had focused on coastal regions and river basins, where Germans had established plantations. The boundary between Papua and Kaiser Wilhelmsland had been established by a joint British-German expedition in 1909; the interior had not been mapped. Since then, Papuan gold prospectors had crossed into German territory which, from the German perspective, made the accuracy of the border essential. 1870–1880 In the 1870s and 1880s German commercial firms began to site trading stations in New Guinea. Agents of J.C. Godeffroy & Sohn reached the Bismarck Archipelago from the Caroline Islands in 1872. In 1875 Hernsheim & Company moved to the Archipelago. 1880–1900 In 1884,