Early sultans and the rise of the slave trade
From 1698 the Sultan of Oman ruled the islands of Zanzibar from Muscat, his capital, through appointed governors and occasional armed raids to put down minor rebellions. To consolidate his grip on the islands, a fort was built in Zanzibar Town, on the site of the Portuguese church, and by 1710 about 50 Omani soldiers were garrisoned there.
By this time, Oman had become a major trading nation. One of its major exports was dates, and the expansion of date plantations created a demand for cheap slave labour. The rules of Islam forbade the enslavement of Muslims, so Africans were imported in large numbers, many of them transported through Zanzibar. It is estimated that there were about 5,000 African slaves in Oman at the beginning of the 18th century, with about 500 new slaves arriving each year. Although most slaves were used on the plantations, others were employed as domestic workers or concubines, and some were re-exported to Persia or India.
In 1744, in Oman, the ruling Yaa'rubi dynasty (which had been in power since 1624) came to an end after a long civil war. It was succeeded by the new Busaidi dynasty led by Ahmed bin Said al Busaidi, an Omani merchant and shipowner. Ahmed was made Sultan of Oman and the east African coast; one of his first moves was to install a new governor in Zanzibar.
At this time, the governors of the east African city states paid allegiance to Oman, but in practice they enjoyed a great deal of autonomy. Zanzibar, Pemba, Lamu and Kilwa were all ruled by members of the Busaidi family, but Mombasa was controlled by a rival Omani family, the Mazrui. In 1746 the Mazruis declared Mombasa independent of Oman, and overthrew the Busaidi force on Pemba. In 1753 they tried to capture Zanzibar, but the governor here remained loyal to Oman and repelled the attack.
During this period, the Mwinyi Mkuu, King Hassan, had died and been succeeded by his son, named Sultan, who in turn was succeeded by his son Ahmed, and then by his grandson Hassan II.
Zanzibar was now a major commercial centre and had also become very important strategically. From the middle of the 18th century there was a flourishing trade in slaves from Zanzibar and Kilwa to the Mascarenes (present-day Mauritius and Réunion). By the 1770s these numbered about 3,000 slaves a year. In the same period Dutch ships came to Zanzibar in search of slaves to work on plantations in the East Indies.
Until this time African slave traders had brought captured slaves to the coast, but by the end of the 18th century the demand for slaves had increased to such an extent that Arab and Swahili traders from the coast and islands were penetrating the African interior. By the 1770s caravan traders had already travelled inland as far as Lake Nyasa (present-day Lake Malawi). For more details, see the East African slave trade box, in a separate section of this site.