The most common weapon of the Aztec was the spears that were known to pierce Spanish armor and were sharp enough that warriors could use them to shave. Another name for their spears was, tepoztopilli. Aztec warriors also used bows & arrows, darts, clubs as well. The Spanish used allies they had made by force or persuasion. The fact that Moctezuma believed Cortés to be a reincarnated god also helped with aiding the Spanish in entering Tenochtitlan. The Spanish uses guns, swords, and cannons as their weapons in the fight against the Aztec but, their greatest weapon proved to be the Small pox virus which they brought to the new world from Europe. Since small pox had been around for a while in Europe, most Europeans had developed and immunity to it but still carried the virus. The Aztecs had never been exposed to the virus so within a number of weeks, a large percent of the Aztec population had been wiped out by the virus.
This belief is known as divine right, which often has been associated with a monarchy, a form of government in which the power of the king or queen is hereditary.