German East Africa. During World War I, an invasion attempt by the British was thwarted by German General Paul von Lettow-Vorbeck, who then mounted a drawn out guerrilla campaign against the British. The post–World War I accords and the League of Nations charter designated the area a British Mandate, except for a small area in the northwest, which was ceded to Belgium and later became Rwanda and Burundi, as well as a small area in the southeast (Kionga Triangle), incorporated to Portuguese East Africa (later Mozambique).
British rule came to an end in 1961 after a relatively peaceful (compared with neighbouring Kenya, for instance) transition to independence. In 1954, Julius Nyerere transformed an organization into the politically oriented Tanganyika African National Union (TANU). TANU's main objective was to achieve national sovereignty for Tanganyika. A campaign to register new members was launched, and within a year TANU had become the leading political organization in the country.
Nyerere became Minister of British-administered Tanganyika in 1960 and continued as Prime Minister when Tanganyika became officially independent in 1961. In 1967 Nyerere's first presidency took a turn to the Left after the Arusha Declaration, which codified a commitment to socialism in Pan-African fashion. After the Declaration, banks were nationalized, as were many large industries.
After the Zanzibar Revolution overthrew the Arab dynasty in neighbouring Zanzibar, which had become independent in 1963, the island merged with mainland Tanganyika to form the nation of Tanzania on 26 April 1964. The union of the two, hitherto separate, regions was controversial among many Zanzibaris (even those sympathetic to the revolution) but was accepted by both the Nyerere government and the Revolutionary Government of Zanzibar owing to shared political values and goals.
From the late 1970s, Tanzania's economy took a turn for the worse. Tanzania was also
