An early Arab/Persian trading center, Zanzibar fell under the Portuguese domination in the 16th. and early 17th. centurybut was retaken by Omani arabs in the early 18th. century . The height of Arab rule came during the reign of Sultan Seyyid Said, who encouraged the development of clove plantations using the islands slve labor.
The Arabs established their own garrisons at Zanzibar, Pemba and Kilwa and carried on a lucrative trade in slaves and ivory. By 1840, said had transferred his capital from Muskat to Zanzibar and established a ruling Arab elite. The islan's commerce fell increasingly into the hands of traders from Indian Subcontinent, whom Said encouraged to settle on the island.
Zanzibar's spices attracted ships from as far away as the US . A US consolate was established on the islan in 1837. The United Kingdom's earlyinterest in Zanzibar was motivated by both commerce and the determination to end the slave trade . In 1822, the british signed the first of a series of treaties with sultan said to curb this trade, but not until 1876 was the sale of slaves finally prohibited.
Monument to the slaves in Zanzibar
The Anglo-German agreement of 1890 made Zanzibar and Pemba a British protectorte . british rule through a sultan remained largely unchanged from the late 19th. century until after WWII.
Zanzibar's political development began in earnest after 1956, when prvision wasfirst made for an election of six nongovernmental members to the legislative council . Two Parties were formed : 1. the Zanzibar Nationalist party (ZNP), representing the dominant Arab and Arabized minorities, 2. the Afro-shirazi party(ASP) led by Abeid Karume and representing the Shirazis and the African majority. In the first election ASP won 3 of the 6 seats, remainder going to independents but it got split and the next election in 1961 ZNP_ZPPP coalitionand ASP had equal no. of seats.
On April 964, Tangnyika united with Zanzibar to form United Rep. of Tanzania.