The Stone Town of Zanzibar is a fine example of the Swahili coastal trading towns of East Africa. It retains its urban fabric and townscape virtually intact and contains many fine buildings that reflect its particular culture, which has brought together and homogenized disparate elements of the cultures of Africa, the Arab region, India, and Europe over more than a millennium.
For many centuries there was intense seaborne trading activity between Asia and Africa, and this is illustrated admirably by the architecture and urban structure of the Stone Town. Zanzibar also has great symbolic importance in the suppression of slavery because it was one of the main slave-trading ports in East Africa, as well as the base from which its opponents such as David Livingstone conducted their campaign.
Two major cultural traditions merged to form the Swahili civilization on the East African coast. A series of harbour towns developed under influences from the interior of Africa and from the lands across the Indian Ocean. There was a loose confederation of small coastal city states known as the Zenj bar (Black Empire) which operated in the 8th-10th centuries. The best preserved of these towns is Zanzibar, the name of which is derived from the Perso-Arabic word meaning 'the coast of the blacks.'
The Swahili economy was destabilized with the arrival of the Portuguese at the end of the 15th century. A church and some merchants' houses were built at Zanzibar, built from simple wattle-and-daub thatched with palm leaves since the 10th century. The Portuguese later added a massive fort on the sea front.
The slave trade, started by the Portuguese, assumed large proportions in the 18th century, when they were required in large numbers for the French sugar plantations in the islands of the Indian Ocean and the Caribbean.
The ruling Islamic dynasty of Zanzibar and its foreign merchants became very rich and embellished the Stone Town with palaces and fine mansions. These were built in a variety of styles and traditions, which were amalgamated and homogenized into a characteristic Swahili architecture. In the 19th century, this Swahili tradition was overwhelmed by new styles brought in by the floods of immigrants: the Minaret Mosque dates from this period. The Omanis introduced a completely different tradition, that of massively built multistorey blocks in mortared coral and with flat roofs. The third architectural component came from India, adding wide verandas, but by the latter half of the 19th century they were constructing elaborately decorated houses reminiscent of the Gujarati haveli.
Modern urban development may be deemed to have begun during the reign of Sultan Barghash (1870-88). His most notable contribution to the architecture of the Stone Town was the House of Wonders, but his greatest legacy was the provision of piped water to the town. The final phase of architectural development came with the arrival of the British in 1890, when Zanzibar became a British protectorate. They imported their colonial architecture but, under the influence of the architect John Sinclair, introduced a number of features derived from the Islamic architecture of Istanbul and Morocco. The last quarter of the 19th century saw increased European missionary activity, resulting in the construction of Anglican and Roman Catholic cathedrals, in the Gothic and Romanesque styles respectively. The Arab ascendancy came to an end with the 1964 revolution and the creation of the United Republic of Tanzania. New constructions built from 1960 to 1970 introduced contemporary styles and materials that were out of harmony with the historic fabric.
The historical evolution of the Stone Town is illustrated by the street pattern. This is one of narrow winding streets resulting from the unplanned building of houses and shops. There are few public open spaces, as many of the houses have their own enclosed spaces. The principal construction material is coralline rag stone set in a thick lime mortar and then plastered and lime-washed.
The vernacular architecture is preponderantly of two-storey buildings with long narrow rooms disposed round an open courtyard, reached through a narrow corridor.