"Most students of American history understand that a dramatic re-peopling of North and South America began in the years after Christopher Columbus first landed in the New World. But they may not realize that it was Africa, not Europe, that formed the wellspring of this repopulation process.
In the 3¼ centuries between 1492 and about 1820, four enslaved Africans left the Old World for every European. During those years, Africans comprised the largest forced oceanic migration in the history of the world. Who were they? Who organized the slaving voyages? Which parts of Africa did they come from? How did they reach the Americas? And where exactly did they go?
Strikingly, we can now provide better answers to such questions for Africans than we can for European migrants. The African slave trade reduced people to commodities, but commodities generated profits, and where there were profits there was generally good record-keeping.
Since the onset of the computer revolution in the early 1960s, early modern business and government records have allowed historians to retrieve information on 35,000 slave voyages from Africa to the Americas and make the information available on the internet. For many of these voyages, we have rich detail on the slave ship itineraries, as well as who was put on board, who survived and how they traveled."