But these Enlightenment reforms proved counterproductive, or perhaps too late, to quell the colonies' demands. The entire history of this Viceroyalty was marked by growing domestic unrest and political instability. Between 1780 and 1782, the Rebellion of Túpac Amaru II inspired a violent Aymara-led revolt across the Upper Peru highlands, demonstrating the great resentment against colonial authorities by both the mestizo and indigenous populations. Twenty-five years later, the Criollos, native-born people of Spanish descent, successfully defended against two successive British attempts to conquer Buenos Aires and Montevideo. This enhanced their sense of autonomy and power at a time when Spanish troops were unable to help.