Revenue stamps of Nigeria
Few revenue stamps of Nigeria and its predecessor states have been issued, since most of the time dual-purpose postage and revenue stamps were used for fiscal purposes. The first revenue-only stamps were consular stamps of the Niger Coast Protectorate and the Southern Nigeria Protectorate, which were created by overprinting postage stamps in 1898 and 1902 respectively.
Source: Wikipedia — Revenue stamps of Nigeria (CC BY-SA 4.0)