On September 1st, Southern Rhodesia became a Crown Colony after refusing to join the Union of South Africa.

Southern Rhodesia, named after British imperialist Cecil Rhodes, was initially administered by the British South Africa Company (BSAC) from the late 19th century. The BSAC had been granted a royal charter to operate, develop, and govern the region, primarily driven by mining interests.

Refusal to Join the Union of South Africa: The Union of South Africa was established in 1910 as a dominion of the British Empire. It was a result of a merger between the British colonies of the Cape of Good Hope, Natal, and the former Boer republics of the Transvaal and the Orange Free State.

There was a proposal for Southern Rhodesia to join this Union, which would've brought it under the governance of South Africa, a nation that would later formally adopt apartheid as its policy. Many settlers in Southern Rhodesia, however, felt distinct from the South Africans, both culturally and economically. They were also wary of becoming a junior partner in the Union, potentially overshadowed by the larger territories. Furthermore, the political dynamics in South Africa, marked by racial tensions and the dominance of the Afrikaner population, made many in Southern Rhodesia apprehensive.

Becoming a Crown Colony: As a result of the refusal to join the Union of South Africa, on September 1, 1923, Southern Rhodesia transitioned from being a territory under the BSAC to becoming a self-governing Crown Colony of the British Empire. This status meant that while it was still under British sovereignty, Southern Rhodesia had its own administrative structures and a greater degree of autonomy in local governance. The white settler population controlled this governance, while the majority Black population had limited political rights.

Aftermath: Southern Rhodesia's status as a Crown Colony would last until 1965 when the white-minority government, unwilling to transition to black majority rule, made a Unilateral Declaration of Independence (UDI). This declaration was not recognized internationally, leading to a period of sanctions and political turmoil. The struggle for majority rule intensified in the 1970s, culminating in the establishment of the independent nation of Zimbabwe in 1980.