The merger of Tanganyika and Zanzibar led to the formation of the United Republic of Tanzania, a pivotal moment in East African history. The events leading to this union were influenced significantly by the Zanzibar Revolution of January 1964, which resulted in the ousting of the Sultan and the establishment of a revolutionary government. This rapid political change caused concern in Tanganyika regarding regional stability and trustworthiness. To address these issues, Julius Nyerere, who had been the prime minister of Tanganyika, and Abeid Karume, the chairman of Zanzibar’s Revolutionary Council, spearheaded discussions to unify their administrations. The decision to merge was not purely strategic; it symbolized an aspiration for post-colonial African unity and increased political cohesion in a region often troubled by tribal and ethnic divisions.

The formal union was accomplished through a series of negotiations, culminating in a treaty signed on April 22, 1964. The agreement stipulated that the united republic would maintain a single, national government while allowing Zanzibar some local autonomy. The inaugural session of the new government took place shortly after the signing, and it heralded the beginning of Tanzania's new political journey. The union was framed as an opportunity to foster socio-economic development and political stability, building on the strengths of both regions while addressing the concerns stemming from the revolution.

In the aftermath of the merger, Tanzania focused on socialist policies under Nyerere, emphasizing self-reliance and collective agriculture. While the union celebrated the potential for national unity, it also faced challenges such as managing the integration of different political ideologies and regional disparities. Yet, the successful merger laid the groundwork for Tanzania’s future as a prominent player in African politics and regional cooperation endeavors.