The Trans-Atlantic slave trade began around the mid-fifteenth century when Portuguese interests moved from the fabled deposits of gold to a more readily available commodity of slaves.
Expanding European powers in the New World lacked one major resource — a labor force. The local indigenous population proved too unreliable. Europeans were unsuitable for the climate and to tropical diseases. Africans were excellent workers, could handle tropical weather and were experienced in raising cattle and agriculture. Slaves for the Trans-Atlantic trade routes were originally from Senegambia down to what is now Angola.