The transatlantic slave trade involved the purchase by Europeans of enslaved men, women, and children from Africa and their transportation to the Americas, where they were sold for profit. Between 1517 and 1867, about 12.5 million Africans began theacross the Atlantic, enduring cruel treatment, disease, and paralyzing fear. Of those, fewer than 11 million survived, with about 40 percent of them going to work on sugarcane plantations in Brazil. Most others labored in the Caribbean, while less than 5 percent ended up in British North America and the United States. The trade originated in the fifteenth century, when Portuguesemariners began patrolling West Africa looking for gold. They ended up with slaves, whom they found useful for building up sugar production on offshore African islands. By the 1580s, the Spaniards were employing the Portuguese to bring larger numbers of enslaved Africans to the Caribbean, where they worked in numerous capacities, most of them urban. The Portuguese transferred their sugar industry to Brazil, gradually replacing enslaved Indians with slaves from Africa. Within a few decades other European powers were converting the Caribbean islands to Brazilian-style sugar plantations, which were in even greater need of enslaved labor. Meanwhile, European traders exploited political instability in Africa to generate additional captives. Most slaves reaching the Chesapeake Bay region before the 1670s were trans-shipped through the English West Indies. The Royal African Company then brought a few Africans directly to , with their numbers rising more steeply after 1698, when the company lost its monopoly. The abolitionist movement, which began in Great Britain, helped end the British trade to the United States, and the United States also outlawed slaving by its citizens. Virginia planters supported these bans, which occurred in 1807–1808, in order to position themselves as suppliers in a new, domestic trade.