Slavery in the early British Americas developed into a critical system of labor that shaped the social, political, and economic foundations of the colonies. Initially, labor in the colonies relied on indentured servitude, where European migrants, often poor or in debt, worked for a fixed period in exchange for passage to the New World. Over time, however, chattel slavery—a system in which people were legally regarded as property—became dominant, especially in the southern and Chesapeake colonies.