when did the trade start
The slave trade began with Portuguese, and some Spanish, traders taking African slaves to the American colonies they had conquered in the 15th century. British sailors became involved in the trade in the 16th century, and the Treaty of Utrecht (1713) gave them the right to sell slaves in the Spanish Empire. In the 18th century, perhaps 6 million Africans were taken to the Americas as slaves, at least a third of them in British ships.