Ruanda-Urundi (rōōän´dä-ōōrōōn´dē), former colonial territory, central Africa, now divided between the independent states of Rwanda and Burundi. The original inhabitants of the area were the Twa, a Pygmy people, who around AD 1000 were driven into the forests by the numerically superior Hutu, a Bantu-speaking agricultural people who immigrated from the east. Probably in the 15th cent., the pastoral Tutsi entered the area from the north. Although greatly outnumbered by the Hutu, the Tutsi gained dominance over them and by the 19th cent. had established two centralized states, Rwanda and Burundi. The first Europeans to explore the region were Oskar Baumann (in 1892) and Graf von Götzen (in 1894). Germany had gained rights to the region at the Conference of Berlin (1884–85), but only began to administer (as parts of German East Africa) Burundi in 1897 and Rwanda in 1907. During World War I, Belgium conquered (1916) the region, and, in 1924, Ruanda-Urundi was formally constituted a mandate of the League of Nations under Belgian rule. In 1946 it became a UN trust territory. Under neither the German nor the Belgian administrations was the social structure of Burundi altered, but in Rwanda the Hutu in 1960–61 gained dominance over the Tutsi. There was little economic development during the colonial period, but missionaries gained many adherents for Christianity. When Ruanda-Urundi achieved independence on July 1, 1962, it was split into two territories, Rwanda and Burundi, and by 1964 all common administrative bodies had been dissolved.