The history of Anglican Diocese of Zanzibar is well inter-related with the history of University Mission of Central Africa and the liberation of Slave Trade in Zanzibar. Slave trade in Zanzibar was initiated by Portuguese who traded slaves in the 15 century. Portuguese were conquered in the war by the Oman in 1549. Zanzibar gradually built her transit trade from economic foundations achieved in the later part of the 18th century. steereFrom the early decades of the 19th century, Said bin Sultan (ruler of Zanzibar 1804 – 1856) moved his Capital from Muscat Oman to Zanzibar and encouraged among other things a broad range of commerce in the region. Slave trade was part of the Zanzibar commerce. The slave trade was promoted Under the Oman Arab rule and resulted of opening new slave market at Mkunazini. The Arabs continued slave trade until it was abolished by treaty of June 6, 1873. Slaves were obtained from the open market and about half of them were formerly captured from the mainland. They were transited at coastal ports such as Kilwa, Kaole, Bagamoyo and Pangani (on the mainland coastline) before packed on board in the dhows to Zanzibar.

Most slaves were procured in the region around Lake Nyassa. The journey down to the coast caused much suffering and pain to slaves, some died of exhaustion, disease, malnourishment, and whoever attempted to escape was shot. Bigger external demands for slaves and also ivory, as well as higher prices for slaves, offered in the coastal ports enticed the coastal traders to heatedly search the interior. Havislavesng purchased slaves in Zanzibar, Arab dealers repacked them for a long voyage to the northern ports of the Indian Ocean. During the opening years of the century, annual import to Zanzibar is estimated to be about 15,000 slaves; just over 60% of these were re-exported to Arabia, Persia, Egypt and other eastern countries in the northern ports of the Indian Ocean where there was a demand for slave labour. And perhaps some we resold to Europe in the early years.

 
The Zanzibar port competed with other slave trade centres on the eastern coast of Africa such as Kilwa in Tanzania Mainland and Quelimane in Mozambique. In the middle of the 19th century however, Zanzibar became the hub of all the important trades in Eastern Africa, superseding all other centres and turned into a major slave trade centre for the whole region of Eastern Africa. A large open slave market that developed at Mkunazini in the Zanzibar town was the greatest distribution centre for slave in East Africa. The slaves were received here from various parts of Eastern and central Africa, auctioned and flicked through before dealers bought them. It is estimated that a well-attended market comprised more than six hundred slaves and buyers altogether. The market provided a source of slaves for most Zanzibar plantation labour. The slaves did the chores. The site of the former slave market is reputed to be the last open slave market in East Africa and the world as a whole. Slavery here was largely Arab and African controlled and not linked with the slave trade which took people to the USA and Caribbean.

The greatest of the history of Anglican Diocese of Zanzibar commenced after Dr. Livingstone expeditions, which David_Livingstone_by_Frederick_Havillhe had made between 1853 and 1856 in East and Central Africa. He made strong speeches against slavery and its trade; he wished to change the uncivilized and dark lives he saw in his expeditions. Also he reported about wars taking place among tribes, the slave and ivory trades and all evil events he saw and the need for missionaries in the East and Central Africa, eventually after Livingstone’s speeches that inspired many of the students and members of the universities’ family. The society of University Mission to Central Africa (U.M.C.A.) was formed 1860, with their mission of stopping slave trade and spreading the gospel of Jesus Christ in this part of Africa. The first party of U.M.C.A. missionaries led by Bishop Charles Fredrick Mackenzie, arrived in the central Africa, 1861 not in Zanzibar but in the Shire highlands, which is today Malawi. Bishop Charles Mackenzie was consecrated in 1860 and the next year sailed up the Zambezi and Shire rivers with a small group to start work.

The Slave market at Mkunazini was closed in June 1873 and the land was acquired by the missionary’s in September 1873 eventually the Cathedral was erected from December 1873 – 1880 by Bishop Edward Steere. When Bishop Steere died, Bishop Charles Allan Smithies succeeded Steere and he became the first bishop of UMCA to be titled Bishop of Zanzibar.

In the regular session of the Synod of the Diocese of Zanzibar and Tanga held from July 15 – 19th 1996 at Korogwe, it was resolved to establish two separate Dioceses namely, that of Tanga and of Zanzibar within a period of three years beginning January 1997. It was envisaged that the new Diocese of Zanzibar would be established in the years 2000.

In January 14, 2001 the inauguration of the Diocese of Zanzibar became possible with full diocesan authority and close higher leadership. The diocese had 5 priests, 4 parishes and 3 Sub-parishes. This was followed by the consecration of a new Bishop on August 24, 2002, ninth bishop of Zanzibar in chronology, the Rt. Revd. Douglas Mathew Toto who succeeded the retired Archbishop John Ramadhani. Bishop Douglas Toto served the diocese for a period of 3 and half years only, he died 9th of February 2006. Since then the diocese is seeking to fill the position of the diocesan bishop, the house of bishops has received names of the priests from Zanzibar who are possible candidates for the bishopric election. During the absence of diocesan bishop, Rev. Canon Matthew Mhagama who helped bishop Toto as a Vicar General lead a diocese for a period of 4 years February 2006 – December 2010 and succeeded by Rev. Michael Hafidh who is the current bishop.