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
Sultanate of Zanzibar over the last of his dominions, Zanzibar. In 1698, Zanzibar became part of the overseas holdings of Oman after Saif bin Sultan, the Imam of Oman, defeated the Portuguese in Mombasa, in what is now Kenya. In 1832 or 1840, Omani ruler Said bin Sultan moved his court from Muscat to Stone Town on the island of Unguja (that is, Zanzibar Island). He established a ruling Arab elite and encouraged the development of clove plantations, using the island's slave labour. Zanzibar's commerce fell increasingly into the hands of traders from the Indian subcontinent, whom Said encouraged to settle on the