He became wealthy from the growing of tobacco and became a property owner and was one of the first people in Virginia to have his RIGHT to own a slave legally recognized.
Indentured servants agreed to work 4-7 years in exchange for passage to the Colonies. After the indenture cost was paid off they were free. Slaves were brought to America against their will and there was no "working it off" to gain freedom.
Allegedly the Dutch introduced indenture to the Colonies in 1619. There are various other alleged "beginnings" of the indenture process and also the bringing in of slaves and I guess you just choose the one you like best.
