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 furthered the country's progress toward abolishing slavery. According to the 16th-century explorer Leo Africanus, the native inhabitants of the Zanzibar (Zanguebar) sultanate were for the most part pagans with curly hair and a black complexion. However, the denizens of the northernmost Zanzibar kingdom of Malindi were Muslims of an almost white complexion, with some pagan black inhabitants among them. Until 1884, the Sultans of Zanzibar controlled a substantial portion of the Swahili Coast, known as Zanj, and trading routes extending further into the continent, as far as Kindu on the Congo River. That year, however, the Society for German Colonization