The Atlantic Slave Trade:

What spurred (or prompted) the growth of the slave trade in the Americas?

The need of labor in plantations in the Spanish and British colonies as a consequence of the great mortality of the local Native Americans wiped out by Old World's diseases they had no immune defense for. These plantations produced commodities in high demand in Europe such as sugar, tobacco and cotton. Even though slavery had ben abolished in Europe by the Catholic Church as early as the sixth century, the chances of becoming rich by means of producing the above mentioned crops were so high that even the Church overlooked this highly immoral practice.