European missionaries began settling in the area from Mombasa to Mount Kilimanjaro in the 1840s, nominally under the protection of the Sultan of Zanzibar. The Imperial British East Africa Company began operations in the area in 1888, also by permission of the sultan, and after 1890 nominally administered Uganda as well.
However, the company began to fail, and on July 1, 1895 the British government proclaimed a protectorate, and in 1902 made the Uganda territory part of the protectorate also. The capital was shifted from Mombasa to Nairobi in 1905, and on July 23, 1920 the protectorate became the colony of Kenya.
The early missionaries sent letters by runner to forwarding agents at Zanzibar. Post offices opened at Mombasa and Lamu in 1890, and after some initial surcharges of British postage stamps with values of 1/2, 1, and 4 annas, the Company issued stamps using a symbolic sun and crown design and inscribed "IMPERIAL BRITISH EAST AFRICA COMPANY", all valued in annas and rupees. Shortages between 1891 and 1895 resulted in a variety of surcharges on these, and the protectorate in 1895 was marked by overprints reading "BRITISH / EAST / AFRICA" and overprints of "British / East / Africa" on stamps of India. The protectorate joined the Universal Postal Union at this time.
in 1896 a series depicting Queen Victoria was issued, inscribed "BRITISH EAST AFRICA", although these ran short in 1897 and stamps of Zanzibar were overprinted as the stamps of India had been previously. A number of post offices opened along the Uganda Railway, which was started in 1896 at Mombasa and reached Kisumu on Lake Victoria in 1902.
In 1901 the postal administration was merged with that of Uganda, and in 1904 stamps issued for the combined East Africa and Uganda Protectorates came into use.Stamps and postal history of British East Africa