Tanzania was closely involved in several groups and organisations that aided the liberation struggle. Of these, the most well-known was the Organisation of African Unity (OAU). Nyerere was a strong proponent of the formation of such an organisation, and when it was established in 1963 Tanzania was a founding member
On 9 December 1961, Tanganyika became independent, though retaining the British monarch as Queen of Tanganyika, and Nyerere became Prime Minister, under a new constitution. On 9 December 1962, a republican constitution was implemented with Mwalimu Julius Kambarage Nyerere as Tanganyika’s first president.
Following their respective independence in 1961 and 1963, the two entities merged in 1964 to form the United Republic of Tanzania. The countries had joined the British Commonwealth in 1961 and Tanzania is still a member of the Commonwealth as one republic