The Aztec Empire was conquered by the Spanish Empire in 1521 under the leadership of Hernán Cortés. Cortés and his soldiers, along with indigenous allies who opposed Aztec rule, launched an expedition that led to the downfall of the powerful empire. The conquest was facilitated by various factors, including superior weaponry, diseases brought by Europeans, and internal dissent among the Aztecs. This event marked the beginning of Spanish colonization in the Americas and had a profound impact on the indigenous populations, leading to significant cultural, social, and political changes in the region.