1780s–1880s: (The East African Slave Trade’s Intense Century — Russian Expansion Cutting Off Muslim World’s Traditional Sources, French Indian Ocean Plantati…

1780s–1880s: (The East African Slave Trade’s Intense Century — Russian Expansion Cutting Off Muslim World’s Traditional Sources, French Indian Ocean Plantations, Brazilian Traders Crossing to the Indian Ocean, Zanzibar’s Clove Plantations Absorbing Mainland Slaves, and Exports Rising from 6,000 a Year in 1800 to 70,000 at the Peak in the 1860s): An East African slave trade had existed for centuries, but it increased dramatically from the 1780s onward for several converging reasons. The expansion of the Russian empire had begun to cut off supplies of slaves from traditional regions to the Muslim world, which then looked to East Africa as a source whose potential had not been fully tapped. There was also heightened demand for slaves for the sugar and coffee plantations on the French islands in the Indian Ocean, expanding from the 1770s. In the early nineteenth century, increasing demand came from Brazil, as older Atlantic sources declined and plantations expanded — Brazilian traders made the longer journey from the southern Atlantic into the Indian Ocean, purchasing slaves from Mozambique and the Zambezi valley. Most significantly, new crops were being cultivated on Zanzibar and Pemba — clove plantations in particular, owned by Arab rulers and often backed by Indian capital, absorbed slaves from the mainland. The East African slave trade entered an intense phase lasting approximately a century, from the 1780s to the 1880s. By 1800, slave exports may have reached around six thousand a year, rising to between twenty and thirty thousand by the 1820s; at the peak in the 1860s, some seventy thousand slaves a year were being exported, all from the interior, with the raiding-and-trading frontier advancing ever further toward the Great Lakes and eastern Congo.