The British South Africa Company established governance in 1890 in what would become Zambia and Zimb

The British South Africa Company established governance in 1890 in what would become Zambia and Zimbabwe [and including the Kingdom of Barotseland because colonialism], calling the region Rhodesia (after Cecil Rhodes, the man behind the money).  Eventually, the region was split into Northern and Southern Rhodesia as protectorates of the British Empire, but they were politically tied together again in the late 1950s, along with Nyasaland (Malawi), for a brief stint at confederation, before all three (Zambia, Zimbabwe, and Malawi) all gained independence in the mid-1960s.  [But not Barotseland.]  Imperialism!

Stamp details:
Stamp on top:
Issued in: 1910
From: Salisbury, Rhodesia
MC #101

Middle left:
Issued in: 1922
From: Salisbury, Rhodesia
SG #296

Middle right:
Issued on: July 1, 1954
From: Salisbury, Federation of Rhodesia and Nyasaland
MC #1

Stamp on bottom:
Issued on: September 11, 1963
From: Salisbury, Federation of Rhodesia and Nyasaland
MC #51

Recognized as a sovereign state by the UN: No
Claimed by: Republic of Zambia; Republic of Zimbabwe; Republic of Malawi
Member of the Universal Postal Union: No