Zanzibar Revolution
Tanzania attained its independence as Tanganyika Territory from the United Kingdom in 1961 with the Tanganyika African National Union (TANU) forming its first government. Following the Zanzibar Revolution in 1964, it merged with the People's Republic of Zanzibar and Pemba to form the United Republic of Tanganyika and Zanzibar (present day Tanzania). It thereafter became a one-party state with TANU and the Afro-Shirazi Party (ASP) being the only parties operating on the mainland and the Zanzibar Archipelago respectively.