Final answer:
Diego Velazquez sent 900 men to capture Cortes because Cortes disobeyed his orders, highlighting a conflict. This event demonstrates the complex dynamics of Spanish exploration and conquest, involving superior military tactics, alliances with indigenous peoples, and the impact of diseases like smallpox.
Step-by-step explanation:
The fact that Diego Velazquez sent 900 men from Cuba to capture Cortes implies that there was a conflict between Velazquez and Hernán Cortés. Velázquez, the governor of Cuba, had revoked Cortés's commission, but Cortés disobeyed and continued with his expedition.
This act of defiance led Velazquez to dispatch a force to detain Cortés. The Spanish conquest under Cortés, facilitated by military tactics and advanced weaponry, including steel armor and horses, was further aided by alliances with indigenous groups, such as the Tlaxcalans, who opposed Aztec rule. These factors, combined with the devastating effect of smallpox upon the Aztec population, contributed to the eventual downfall of the Aztec Empire.