The Spanish conquest of the Aztec Empire resulted in the downfall of one of the most powerful indigenous civilizations in the Americas. Led by Hernán Cortés in 1519, the Spanish forces formed alliances with other indigenous groups who opposed Aztec rule. By 1521, after a series of battles and a devastating epidemic of smallpox that decimated the Aztec population, Cortés captured the capital city of Tenochtitlán. The conquest led to the establishment of Spanish colonial rule in Mexico, significant cultural exchanges, and the imposition of Christianity, profoundly impacting the social and political landscape of the region for centuries.