The History of the United States, 2nd Edition
An Economy of Slaves
S1 E6:
The transition of settlements to stable commercial success would not have been possible without a source of cheap labor. America's immensity of land and lack of labor to develop it required forced migration of laborers: convicts, indentured servants, beggars. But a less expensive and more permanent source of labor was the 11 million Africans who were torn from their homes to be slaves.