The revolutionary leader who pioneered the struggle against colonial oppression in the Americas was Simón Bolívar. Bolívar, often called "El Libertador," played a crucial role in the independence movements across several South American countries, including Venezuela, Colombia, Peru, and Bolivia. He advocated for the establishment of republican governments free from Spanish colonial rule. His vision of a united Latin America, sometimes referred to as Gran Colombia, inspired generations and made him a symbol of liberation and nationalism in the region, shaping the history of South America.