No; they only started to decline when the Spanish started to attack them.
The Aztecs had a lot of enemies and when the Spanish conquistadors arrived to Mexico the Aztec enemies were more than happy to help the Spanish destroy the Aztecs.
decline of the Aztecs
Atahualpa
probably the spanish and europeans
Montezuma II
Montezuma II was the leader.
montezuma the II
The Aztecs did not practice Catholicism before the Europeans arrived; they had no exposure to it until then.
Montezuma II (1466 - 1520) qualified as such.
Maya, Incan, Aztecs
The Aztecs had a lot of enemies and when the Spanish conquistadors arrived to Mexico the Aztec enemies were more than happy to help the Spanish destroy the Aztecs.
1798. The Europeans invaded the Aztecs by travelling to Mexico on canoes.
decline of the Aztecs
The first one came when Cortez came to the Americas to look for gold. He found the Aztecs who gave them riches to go away; however, Cortez kidnapped Montezuma, ransoming the whole Aztec wealth.
Some didn't like Aztec rule, so they were more likely to go against them and unite with the Spanish conquistador Hernán Cortés. The Spaniard's iron, steel, and gunpowder defeated the Aztecs. In addition, the Aztecs fell prey to new diseases the Europeans brought with them.
The Spanish Conqiustadors. They may have only arrived with 600 men and 16 Horses but they quickly gained the trust of the Aztecs, who believed they were gods, and preformed a swift coup d'etat. Nevermind the fact that the Spanish did have technologically advanced weapons, that still wouldn't have been enough. What ultimately brought the downfall of the Aztecs was the combined alliance between rival indigenous tribes and the Spaniards. Many other factors helped speed up the conquering of the Aztecs such as the many new diseases the Europeans brought to the Americas such as syphilis, influenza, and small pox.
Atahualpa