At first, most of the slaves were Guanche, but they inconveniently and rapidly died from the new diseases. To replace the dead, the colonists imported Africans to work the sugar plantations. West African societies had long enslaved war captives and convicted criminals for sale to Arab traders, who drove them in caravans across the Sahara to the Mediterranean. This caravan trade was relatively small in scale, with a volume of only about one thousand slaves per year in the early fifteenth century.
