Northern Tanganyika's famed Olduvai Gorge has provided rich evidence of the area's prehistory, including fossil remains of some of humanity's earliest ancestors. Discoveries suggest that East Africa may have been the site of human origin.

Little is known of the history of Tanganyika's interior during the early centuries of the Christian era. The area is believed to have been inhabited originally by ethnic groups using a click-tongue language similar to that of Southern Africa's Bushmen and Hottentots. Although remnants of these early tribes still exist, most were gradually displaced by Bantu farmers migrating from the west and south and by Nilotes and related northern peoples. Some of these groups had well-organized societies and controlled extensive areas by the time the Arab slavers, European explorers, and missionaries penetrated the interior in the first half of the 19th century.

The coastal area first felt the impact of foreign influence as early as the 8th century, when Arab traders arrived. By the 12th century, traders and immigrants came from as far away as Persia (now Iran) and India. They built a series of highly developed city and trading states along the coast, the principal one being Kibaha, a settlement of Persian origin that held ascendancy until the Portuguese destroyed it in the early 1500s.

The Portuguese navigator Vasco da Gama explored the East African coast in 1498 on his voyage to India. By 1506, the Portuguese claimed control over the entire coast. This control was nominal, however, because the Portuguese did not colonize the area or explore the interior. Assisted by Omani Arabs, the indigenous coastal dwellers succeeded in driving the Portuguese from the area north of the Ruvuma River by the early 18th century. Claiming the coastal strip, Omani Sultan Seyyid Said (l804-56) moved his capital to Zanzibar in 1841.

European exploration of the interior began in the mid-19th century. Two German missionaries reached Mt. Kilimanjaro in the 1840s. British explorers Richard Burton and John Speke crossed the interior to Lake Tanganyika in 1857. David Livingstone, the Scottish missionary-explorer who crusaded against the slave trade, established his last mission at Ujiji, where he was "found" by Henry Morton Stanley, an American journalist-explorer, who had been commissioned by the New York Herald to locate him.

German colonial interests were first advanced in 1884. Karl Peters, who formed the Society for German Colonization, concluded a series of treaties by which tribal chiefs in the interior accepted German "protection." Prince Otto von Bismarck's government backed Peters in the subsequent establishment of the German East Africa Company.

In 1886 and 1890, Anglo-German agreements were negotiated that delineated the British and German spheres of influence in the interior of East Africa and along the coastal strip previously claimed by the Omani sultan of Zanzibar. In 1891, the German Government took over direct administration of the territory from the German East Africa Company and appointed a governor with headquarters at Dar es Salaam.

Although the German colonial administration brought cash crops, railroads, and roads to Tanganyika, European rule provoked African's resistance, culminating in the Maji Maji rebellion of 1905-07. The rebellion, which temporarily united a number of southern tribes and ended only after an estimated 120,000 Africans had died from fighting or starvation, is considered by most Tanzanians to have been one of the first stirrings of nationalism.

German colonial domination of Tanganyika ended after World War I when control of most of the territory passed to the United Kingdom under a League of Nations mandate. After World War II, Tanganyika became a UN trust territory under British control. Subsequent years witnessed Tanganyika moving gradually toward self-government and independence.

In 1954, Julius K. Nyerere, a school teacher who was then one of only two Tanganyikans educated abroad at the university level, organized a political party--the Tanganyika African National Union (TANU). TANU-supported candidates were victorious in the Legislative Council elections of September 1958 and February 1959. In December 1959, the United Kingdom agreed to the establishment of internal self-government following general elections to be held in August 1960. Nyerere was named chief minister of the subsequent government.

In May l961, Tanganyika became autonomous, and Nyerere became Prime Minister under a new constitution. Full independence was achieved on December 9, 1961. Mr. Nyerere was elected President when Tanganyika became a republic within the Commonwealth a year after independence.

An early Arab/Persian trading center, Zanzibar fell under Portuguese domination in the 16th and early 17th centuries but was retaken by Omani Arabs in the early 18th century. The height of Arab rule came during the reign of Sultan Seyyid Said, who encouraged the development of clove plantations, using the island's slave labor.

The Arabs established their own garrisons at Zanzibar, Pemba, and Kilwa and carried on a lucrative trade in slaves and ivory. By 1840, Said had transferred his capital from Muscat to Zanzibar and established a ruling Arab elite. The island's commerce fell increasingly into the hands of traders from the Indian subcontinent, whom Said encouraged to settle on the island.

Zanzibar's spices attracted ships from as far away as the U.S. A U.S. consulate was established on the island in 1837. The United Kingdom's early interest in Zanzibar was motivated by both commerce and the determination to end the slave trade. In 1822, the British signed the first of a series of treaties with Sultan Said to curb this trade, but not until 1876 was the sale of slaves finally prohibited.

The Anglo-German agreement of 1890 made Zanzibar and Pemba a British protectorate. British rule through a Sultan remained largely unchanged from the late 19th century until after World War II.

Zanzibar's political development began in earnest after 1956, when provision was first made for the election of six nongovernmental members to the Legislative Council. Two parties were formed: the Zanzibar Nationalist Party (ZNP), representing the dominant Arab and "Arabized" minority, and the Afro-Shirazi Party (ASP), led by Abeid Karume and representing the Shirazis and the African majority.

The first elections were held in July 1957. The ASP won three of the six elected seats, with the remainder going to independents. Following the election, the ASP split; some of its Shirazi supporters left to form the Zanzibar and Pemba People's Party (ZPPP). The January 1961 election resulted in a deadlock between the ASP and a ZNP-ZPPP coalition.

On April 26, 1964, Tanganyika united with Zanzibar to form the United Republic of Tanganyika and Zanzibar, this was renamed the United Republic of Tanzania on October 29, 1964.

Zanzibar received its independence from the United Kingdom on December 19, 1963, as a constitutional monarchy under the sultan. On January 12, 1964, the African majority revolted against the sultan and a new government was formed with the ASP leader, Abeid Karume, as President of Zanzibar and Chairman of the Revolutionary Council. Under the terms of its political union with Tanganyika in April 1964, the Zanzibar Government retained considerable local autonomy.

To form a sole ruling party in both parts of the union Nyerere merged TANU with the Zanzibar ruling party, the Afro-Shirazi Party (ASP) of Zanzibar to form the CCM (Chama cha Mapinduzi-CCM Revolutionary Party), on February 5, 1977. The CCM was to be the sole instrument for mobilizing and controlling the population in all significant political or economic activities. He envisioned the party as a "two-way street" for the flow of ideas and policy directives between the village level and the government. On April 26, 1977, the union of the two parties was ratified in a new constitution. The merger was reinforced by principles enunciated in the 1982 union constitution and reaffirmed in the constitution of 1984.

President Nyerere stepped down from office and was succeeded as President by Ali Hassan Mwinyi in 1985. Nyerere retained his position as Chairman of the ruling party for 5 more years and was influential in Tanzanian politics until his death in October 1999. The current President, Benjamin Mkapa, was elected in 1995 and re-elected for a second five-year term in 2000. Zanzibar President Amani Abeid Karume, the son of Zanzibar’s first president, was elected in 2000, in general elections that were marked by widespread irregularities throughtout the Isles. His predecessor, Salmin Amour, was first elected in single-party elections in 1990, then re-elected in 1995 in Zanzibar’s first multi-party elections. These elections, also were tainted by widespread irregularities on Zanzibar.