The East African nation of Tanzania dates formally only from 1964, when it was formed out of the union of the much larger mainland territory of Tanganyika and the coastal archipelago of Zanzibar. The former was a colony and part of German East Africa from the 1880s to 1919, when, under the League of Nations, it became a British mandate until independence in 1961. It served as a military outpost during World War II, providing financial help, munitions, and soldiers. Zanzibar was settled as a trading hub, subsequently controlled by the Portuguese, the Sultanate of Oman, and then as a British protectorate by the end of the nineteenth century. Julius Nyerere would rule the country for decades. Following Nyerere's retirement in 1985, various political and economic reforms began.
Tanzania is home to some of the oldest human settlements unearthed by archaeologists, including stone tools and fossils of hominids found in and around Olduvai Gorge in northern Tanzania, an area often referred to as "The Cradle of Mankind". Acheulian flint tools were found there by Louis Leakey in 1931, following up similar tool finds made by Hans Reck in 1913, and more importantly older more primitive stone tools were also found - these were the first examples of the oldest human technology ever discovered, subsequently known throughout the world as Oldowan after Olduvai Gorge. The first hominid skull in Olduvai Gorge was discovered by Mary Leakey in 1959, and named (Zinj or Nutcracker Man), the first example of Paranthropus boisei, and is thought to be over 1.8 million years old. Other finds including Homo Habilis fossils were subsequently made. At nearby Laetoli the oldest known hominid footprints, the Laetoli footprints, were discovered by Mary Leakey in 1978, and estimated to be about 3.6 million years old and probably made by Australopithecus afarensis . The oldest hominid fossils ever discovered in Tanzania also come from Laetoli and are the 3.6 to 3.8 million year old remains of Australopithecus afarensis – Louis Leakey had found what he thought was a baboon tooth at Laetoli in 1935 (which was not identified as afarensis until 1979), a fragment of hominid jaw with 3 teeth was found there by Kohl-Larsen in 1938–39, and in 1974–75 Mary Leakey recovered 42 teeth and several jawbones from the site.
Reaching back about 10,000 years, Tanzania is believed to have been populated by hunter-gatherer communities, probably Khoisan speaking people. Between three and six thousand years ago, they were joined by Cushitic-speaking people who came from the north, into which the Khoisan peoples were slowly absorbed. Cushitic peoples introduced basic techniques of agriculture, food production, and later, cattle farming.
About 2000 years ago, Bantu-speaking people began to arrive from western Africa in a series of migrations. These groups brought and developed ironworking skills and new ideas of social and political organization. They absorbed many of the Cushitic peoples who had preceded them, as well as most of the remaining Khoisan-speaking inhabitants. Later, Nilotic pastoralists arrived, and continued to immigrate into the area through to the 18th century