After the conquest of the Caribbean, Mexico, and Peru, Spanish dominance in the Americas was maintained through a combination of “soft” and “hard” power: a mixture of armed coercion and an elaborate legal-administrative apparatus which ensured that tension rarely escalated into full-blown conflict. The sturdiness of Spain’s empire may also be attributed to other significant factors, including epidemiology (differential immunity), topography, and the avoidance of certain types of military engagement, all of which tended to intersect with or reinforce the deployment of “soft” and “hard” power. There were at least three broad threats to Spain’s dominance: external enemies, particularly rival European states covetous of the economic advantages Spain obtained from its New World dominions; unsubdued Amerindians on the fringes of Spanish settlement, who clung to their autonomy and effectively controlled vast swathes of territory through to the end of the colonial period; and an internal, heterogeneous group from all rungs of the socioeconomic ladder, from wealthy, privileged merchants to mistreated African slaves. At some point or other from 1521 until 1808, an internal challenge to Spanish dominance emerged from every sector of colonial society. Whether by design or felicitous coincidence, external and internal threats to Spanish dominance were rarely coterminous, which may help to explain the empire’s resilience and longevity.