How was the atlantic slave trade different in the 1400s and 1500s than it was in the 1600s?

Atlantic slave trade different in the 1400s and 1500s than it was in the 1600s because in the 1400 and 1500 the majority of slaves were sold to European Countries, where in the 1600s slaves were principally sold across the Atlantic. This fact reflects the complex dynamic of a society that was rapidly changing due to the new discoveries and new technological advances.