There are many casual factors to consider in answering questions on why the Aztec Empire was taken so quickly by the Europeans led by Hernan Cortes. The factors can help understand and explain the conquest of Mexico. Hernan Cortes was able to conquer the Aztecs for several different reasons. All together these reasons allowed Cortes to have the upper hand in the conquest of the new world. The Spanish brought several diseases into Mexico in witch they were immune to but the Aztecs were not. The spread of diseases such as small pox reduced the Aztec population and furthered Cortes" success unintentionally. Also, the Aztecs had a harsh tribute system that was not popular among the peoples of Mexico. This cruel tribute system allowed Cortes to act as though he was a liberator. Another factor that furthered the Spanish conquest was Dona Marina, she proved to be an imperative part in translating local dialects. Another important aspect of the Spanish success was due to Montezuma's belief in the omens and supernatural events. A predominant reason for the Spanish success was due to their weaponry especially their armor and firepower. The most important reason of all was that of Cortes" Indian allies such as the Tlaxcalans who made up the majority of his combined army. All these reasons worked together to allow Cortes with an inadequate amount of conquistadors to conquer the Aztec Empire of millions of people. .
The Aztec's harsh tribute system allowed Cortes to act as a liberator of the indigenous people. Bernal Diaz in his report shows this, "Tlaxcala, whose people were linguistically and culturally akin to the Mexica, but who were also their traditional political enemies." The process of human sacrifice was extremely common and was feared by the majority of the common people. The Aztecs as a nourishment for the Sun and all other gods needed human sacrifice. As the majority of those who were sacrificed were war captives who opposed the Aztecs, they obviously greatly feared the brutal tribute system.