The coastal region of East Africa had been part of a long-distance trade system since the beginning of our era, connected to the Red Sea by sailing ships. From around the 8th to 9th century, Swahili culture spread along the coast, creating a chain of Islam-influenced cities from trading posts. Starting in 1885, the Society for German Colonization claimed parts of the interior and attempted to establish a colony. Their rule collapsed in 1888 during the uprising of the East African coastal population, after which the German Empire conquered the territories that would become the colony of German East Africa, which included present-day mainland Tanzania as well as Rwanda and Burundi. During World War I, the German Schutztruppe, under the leadership of Paul von Lettow-Vorbeck, fought until Kri.