Spanish conquered Aztecs in 1521. The city of Tenochtitlan fell to Hernan Cortez and his allies. Cortez had arrived on the shores several months before. Montezuma, leader of the Aztecs, felt Cortez might be one of their gods, Quetzalcoatl. Montezuma made the Spanish feel welcome, but ultimately the conquistadors turned on the Aztecs. Children can read some great background information at: Aztecs.