Hernan Cortes led the Spanish conquest of the Aztec Empire in 1519. The Aztecs initially welcomed Cortes and the Spanish as guests, believing Cortes to be the returning Aztec god Quetzalcoatl. However, Cortes betrayed the Aztecs and attacked the city of Tenochtitlan. While the Aztecs had a powerful empire, several factors contributed to their defeat, including their religious beliefs, diseases brought by the Spanish, and Spanish weapons and tactics. The fall of the Aztec Empire marked the beginning of Spanish control over central Mexico.