Cortés' conquest of the Aztec Empire was a pivotal event in early 16th century when Spanish conquistador Hernán Cortés led an expedition that resulted in the fall of the Aztec capital, Tenochtitlán, and the subsequent establishment of Spanish rule over large parts of present-day Mexico. This event is crucial for understanding the broader patterns of Spanish exploration and conquest, highlighting themes of European imperialism, indigenous resistance, and the drastic changes to the Americas following contact with Europeans.