Through the years, Zanzibar stamps have always been fascinating - Cesare Giacomelli, owner of the House of Spices has gathered this collection of photos.
In 1698 the Arabs of Muscat and Oman, assisted by English ships, captured the Portuguese fort at Mombasa. Gaining control of the whole area, Zanzibar and Pemba fell into their hands. In 1747 Ahmed bin Said el-Busaidi, founder of the Busaidi dynasty, still reigning in Zanzibar, became ruler of Muscat and Oman.
In around 1833 the Sultan of Oman moved to Zanzibar, and from 1842 onwards there was a British Consul. Zanzibar separated politically from Muscat and Oman in 1861. In 1873 the Sultan agreed, by treaty with Britain, to prohibit the export of slaves from East Africa and to close all public slave markets in his dominions.
In 1886 Britain, France and Germany recognized the sovereignty of the Sultan over the islands and a ten-mile wide strip of about 600 miles in length along the mainland coast.
A post office under Indian administration provided postal services from late 1868 through to early 1869. This was re-opened on 1st October 1875 as a foreign post office having special relations with the Indian Post Office. The use of Indian stamps was obligatory. They can only be detected by their cancellations. Subsequently mail was forwarded via Seychelles or later via Aden or Bombay. The office continued to function until 10th November 1895, the date of transfer from Indian to British East African administration.
The Zanzibar Protectorate post office, administered by the Postmaster-General of British East Africa, operated from 10th November 1895. Supplies of Indian stamps were overprinted with "Zanzibar" at the office of the Zanzibar Gazette.
In 1895 Zanzibar joined the Universal Postal Union and this called for a 2½ annas denomination to cover the foreign letter rate. Supplies of the 2½ annas overprinted stamp not being sufficent, stocks of the 1½ annas were surcharged "2½" in red in December 1895. On 11th May 1896 the 1 anna was similarly surcharged in black, on 15th August the 2 annas was given the surcharge in red and on 15th November the 1½ annas was surcharged in red in a different type. Seven different settings of the "2½" have been catalogued and there are many errors.
In addition to the Zanzibar post office, there were six other post offices on Zanzibar and three offices on Pemba. A French post office operated from 16th January 1889 to 31st July 1904, and a German postal agency operated from 27th August 1890 to 31st July 1891. Zanzibar took control of its own postal services in 1901.
Many stamps covered the reign of Sultan Khalif bin Harub from 1936, when he celebrated his Silver Jubilee. By this time the interests of collectors were being considered and it became possible to obtain sheets with selvedges and marginal markings.
Zanzibar issued a Victory set in 1946 by overprinting definitives, some scenic definitives and a Royal Silver Wedding set in 1948. This last set is the only Zanzibar set bearing a royal image.
In 1964 the Sultan was deposed in a revolution and he was evacuated by the Royal Navy.
The existing stamps were overprinted locally 'Jamhuri 1964'. Forgeries of these are also known.
The Republic is now subsumed into Tanzania.
with thanks for information from Mel Doyle http://www.wokinghamphilatelic.org.uk/index_files/2014news.htm?ckattempt=1