African slaves had been brought to the New World long before the pilgrims ever landed on Plymouth Rock. Yet it would take almost 200 years before slavery became a fixture in the American economy. The number of slaves in America rose dramatically in the late 17th and early 18th century as a result of the rise of the agricultural economy, including tobacco and sugar production. During this period, slavery became a cornerstone of the American South.

First Slaves in the New World

The earliest slaves appeared in America in the early 1500s. Spanish settlers had enslaved Native Americans, but their population dropped by as much as 50 to 90 percent as a result of disease, harsh treatment and fighting, according to the University of Houston's "Digital History" website. The Spanish began using African slaves by the middle of the 16th century to meet their demands for labor instead. When British settlers arrived in America, most of them relied on indentured servitude rather than African slave labor. However, they, too, began purchasing African slaves as their demand for labor outpaced their supply.

End of Slave Trade Monopoly

The reason that British colonists were able to start importing more African slaves is that the Dutch monopoly on the slave trade came to an end. The Dutch had wrested control over the slave trade from the Portuguese and established the West India Trading Company. The Dutch maintained their monopoly from 1600 to 1700. The final blow was the passage of the Navigation Acts forbidding the Dutch from importing slaves into French and English colonies, which comprised much of its trade. The acts were a series of laws that were passed in the last half of the 17th century.

Rise of Southern Economy

The biggest influence on the growth of African slaves in America was the explosion of the agricultural economy in the South. With the Native Americans dying in large numbers and the number of indentured servants not meeting demands for labor, the colonists turned to slaves. Not only were slaves cheaper labor that would increase profits for plantation owners, but they also had extensive knowledge of how to raise crops like tobacco, sugar and rice, as well as how to care for livestock. The number of blacks in the south rose dramatically in the 18th century, going from 8,700 in 1700 to 31400 in 1715 to 80600 in 1730. By 1790, there were 590,500.

Laws Governing Slavery

As the Southern economy became reliant on slave labor, laws were enacted that would ensure the permanency of slave status and help to grow their numbers even more. For example, Virginia passed a law in 1662 that ruled that all children would have the status of their mother at birth. That meant that any child fathered by a slave master with a slave woman would be born a slave and remain a slave until death. Slave owners could now breed their slaves and grow their labor force for free.