a large free workforce and thus obviated the need to use unfree labor on a large scale. Colonial New England's reliance on the labor of free men, women, and children, organized in individual farm households, is called the yeoman or household labor system. There is an important distinction to be made between "societies with slaves", such as colonial New England, and "slave societies", where slavery was so central that it can properly be said to define all aspects of life in that region. The French colony of Saint-Domingue was one of the first American jurisdictions to end slavery, in 1794. Brazil was the last nation in the Western Hemisphere to end slavery, in 1888. Governance The Spanish conquistadores conquered the Aztec Empire, more accurately now referred to by scholars as the Mexica empire, in present-day Mexico, and the Inca Empire, in present-day Peru, with surprising speed, assisted by horses, guns, large numbers of Native allies, and, perhaps above all, by the devastating mortality inflicted by newly introduced diseases such as smallpox. To some extent the prior emergence of the large and wealthy Inca and Mexica civilizations aided the transfer of governance to the Spanish, since these native empires had already established road systems, state bureaucracies and systems of taxation and intensive agriculture that were often inherited wholesale and then modified by the Spanish. The early Spanish conquerors of these empires were also aided by political instability and internal conflict within the Mexica and Incan regimes, which they successfully exploited to their benefit. One of the problems that most European governments faced in the Americas was how to exercise authority over vast expanses of territory. Spain, which colonized Mexico, Central America, and the greater part of South America, established a network of powerful viceroyalties to administer different regions of its New World holdings: the Viceroyalty of New Spain (1535), the Viceroyalty of Peru (1542), the Viceroyalty of New Granada (1717–1739), and the Viceroyalty of Rio de la Plata (1776). The result was strong government that became even stronger during the Bourbon reforms of the 18th century. Britain approached the task of governing its New World territories in a less centralized manner, establishing about twenty distinct colonies in North America and the Caribbean from 1585 onward. Each British colony had its own governor and most would have representative assemblies. Most of the North American Thirteen Colonies that became the United States had