Flag of Zanzibar yellow cloves was added to the flag. On 12 January 1964, John Okello overthrew the Sultan of Zanzibar and adopted a black-yellow-blue tricolour as the flag of the People's Republic of Zanzibar and Pemba. On 29 January, the country's flag was changed to a blue-black-green tricolour with a thin white stripe at the hoist. This design, which was based on the flag of the Afro-Shirazi Party, was the longest-lived of the post-independence flags and eventually formed the basis for the current flag. On 26 April 1964, Zanzibar united with Tanganyika to form the new country of Tanzania and Zanzibar's old
History of Zanzibar Africans died each year before ever reaching the island.) Tippu Tip was the most notorious slaver, under several sultans, and also a trader, plantation owner and governor. Zanzibar's spices attracted ships from as far away as the United States, which established a consulate 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. Under strong British pressure, the