George Bancroft, History of the Colonization of the United States, Vol. 1, 17th edition.

Conditional servitude, under indentures or covenants, had from the first existed in Virginia. The servant stood to his master in the relation of a debtor, bound to discharge the costs of emigration by the entire employment of his powers for the benefit of his creditor. Oppression early ensued: men who had been transported into Virginia at an expense of eight or ten pounds, were sometimes sold for forty, fifty, or even threescore pounds.² The supply of white servants became a regular business; and a class of men, nicknamed spirits, used to delude young persons, servants and idlers, into embarking for America, as to a land of spontaneous plenty.³ White servants came to be a usual article of traffic. They were sold in England to be transported, and in Virginia were resold to the highest bidder; like negroes, they were to be purchased on shipboard, as men buy horses at a fair.⁴ In 1672, the average price in the colonies, where five years of service were due, was about ten pounds; while a negro was worth twenty or twenty-five pounds.⁵ So usual was this manner of dealing in Englishmen, that not the Scots only, who were taken in the field of Dunbar, were sent into involuntary servitude in New England,⁶ but the royalist prisoners of the battle of Worcester;⁷ and the leaders in the insurrection of Penruddoc,⁸