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 received its independence from the United Kingdom as a constitutional monarchy under the Sultan. This state of affairs was short-lived, as the Sultan and the democratically elected government were overthrown on 12 January 1964 in the Zanzibar Revolution led by John Okello, a Ugandan citizen who organized and led the revolution with his followers on the island. Sheikh Abeid Amani Karume was named president of the newly created People's Republic of Zanzibar and Pemba. Several thousand ethnic Arab (5,000-12,000 Zanzibaris of Arabic descent) and Indian civilians were murdered and thousands more detained or expelled, their property either confiscated or destroyed.