The Aztec Empire on the eve of Spanish contact in 1519 When the Spanish reached central Mexico in 1519, they were not entering an empty land or a loose collection of villages. They arrived in the middle of the Aztec Empire, a powerful political system centered on the Valley of Mexico and connected by conquest, alliances, and tribute. The empire did not function like a modern country with fixed borders and direct rule everywhere. Many regions shown on this map were governed by their own local leaders, who remained in place as long as they paid tribute and recognized Aztec authority. Control was strongest near the capital and became more fragile the farther out it extended. This helps explain what the Spanish encountered as they moved inland. When Hernán Cortés and his allies advanced, they entered a landscape shaped by rival city states, heavy tribute demands, and long standing tensions. Not everyone under Aztec dominance saw the empire as legitimate or stable. This map captures a brief moment just before everything changed. Within only a few years, this political system would collapse completely. But in 1519, the Aztec Empire still stood at its height, commanding much of central Mexico through influence rather than uniform control.