The Fall of the Aztecs & Why They Lost
Hernando Cortez was a conquistador. He craved adventure and riches. After the new world was discovered, it did not take long for people to want to colonize and convert the natives. For men like Cortez, religion was an excuse not a driving force. Power, glory, fame, and wealth made him and people like him happy.

Cortez attracted men that liked the same things he did. These men were cruel, vicious, and very violent. They had no problem leaving Europe and making their mark in the new world. In the new world, they were not criminals, but masters of their own destiny.

Kingdoms in Europe would sponsor expeditions to the new world, but for men like Cortez, it had to be very profitable. To find men like Cortez, the pay-off had to be great. The Spanish government decreed that any expedition under their sponsorship would have to give the government 1/5 of whatever they find. It was called the Royal Fifth.

Cortez was a greedy man. He had no intention of giving the government their Royal Fifth. The local government in Cuba got wind of Cortez's plan. The night before Cortez was to sail, the Cuban government went to seize all the ships and put Cortez in jail. They chose the night before because usually the boats are empty because the sailors and conquistadors are partying it up one last time.

Cortez was tipped off of the plan and he closed his ships up, and took whoever was on board. Clearly Cortez sailed with a small crew. Roughly 2/3 of his crew was left in Cuba. He sailed with around 200-300 men.

Call it coincidence or prophecy, but Cortez fit the mold for what was next to come. In the land of the Aztecs, it was the year of the snake, namely the feathered serpent. That was the animal of a special god in the pantheon of Aztec worship, namely Quetzalcoatl. Quetzalcoatl was said to return to liberate and restore the old ways. Quetzalcoatl was to return from the east, and he had some other special physical features:
Quetzalcoatl was to be light skinned

Quetzalcoatl was to have hair of fire

Quetzalcoatl was to speak the language of the gods

Quetzalcoatl was to have gods under him

Quetzalcoatl was to have god-like materials

Cortez followed this physical description very closely:

Cortez was light skinned compared to the Aztecs, especially since he was from Europe

Cortez did have hair of fire, namely red hair.

Cortez did speak a different language, Spanish. Aztecs would have no idea what he was saying.  However, the two languages share similar words.  Also, Cortez had translators that made it seem like he was all knowing.

Cortez did have gods under him, horses. Aztecs never saw an animal as big, as fast, and as strong as a horse.

Cortez did have god-like materials: 3 masted ships; armor; guns; swords; and various other materials that the Aztecs never saw.

Combine these physical characteristics on top of it being the year of the feathered serpent; Cuba being east of Mexico; and a comet was seen early that year by the Aztecs preparing them for Quetzalcoatl, Cortez was the real deal.

Physically he was the real deal, but mentally and behaviorally there were contrast to the prophecy. As Quetzalcoatl, Cortez was to know certain things, respect certain customs, and behave a certain way. Cortez was immediately praised and worshipped by the natives upon his arrival. What he liked most was the gifts of gold and other precious gifts.
Upon receiving an interpreter, Cortez started planning how to find more riches. Cortez decided to enter the Aztec capital and collect as many riches he could get. Being the ruthless fighters and people that they were, Cortez and his soldiers made many blunders on their way to the capital. Murdering, raping, stealing, treating the natives poorly made their entrance into the capital not a day of great joy, but much debate and anxiety.
Montezuma II who was the emperor of the Aztecs was notified about the coming of Cortez to the capital. He knew of the prophecy, the physical resemblance of Cortez to Quetzalcoatl, and also the behavior of the so called gods. This alone may be the most difficult decision a leader at anytime, anyplace, in the history of the world had to make.
Cortez had everything he wanted; power, wealth, land, and the worship of a people. It was not enough. Cortez wished to return to Cuba and eventually Europe a hero. Before he could leave a revolt among the Aztecs left Montezuma dead and the Spanish running. Before they could leave, the conquistadors tried to take as much gold as possible. With only four bridges to leave the capital, many tried to swim with pockets full of gold.

Cortez was smart enough to just leave knowing that he could come back. He did with a larger army, destroying the Aztecs very quickly.
Montezuma could have destroyed the Spanish at any time, but it was too late. There are many reasons why:

1. Montezuma thought that Cortez was the god Quetzalcoatl. This gave the Spanish the ability to enter the capital and attack from within. Think about it. Is it easier to keep people away or throwing them out? There are no barriers to stop a group inside the capital. The goal of war is to capture the capital. The Spanish didn't lose a man and they achieved this.
2. The Spanish had better weapons. Guns were very primitive at this time; however they were still light years ahead of the Aztec weapons of clubs, bows, arrows, spears, and rocks. The Spanish were better protected with armor. The best the Aztecs could produce was wool tightly bounded together. It was lighter than armor, but it could not handle the force of Spanish steal or a bullet.
3. The Aztecs thought the horse was a god. The horse provided something that the Aztecs never saw in this side of the world, an animal with size, speed, strength, and power. The largest animals the Aztecs were introduced to were deer and jaguars. They were scared of the horse. Now, add on the fact that the Spanish used these horses as cavalry, and they become more destructive. Finally, realize that a man sits on top of this god. Psychologically, Aztecs were thinking if this man/god could control a god, which is the horse, how much of a chance would an Aztec have if they had to fight these men hand-to-hand?

4. Disease of the European. European germs and virus' killed more people of the New World than any army. Even before Europeans got off the boat Native Americans were dying. They had no immunity from even the most simple of viruses like the common gold and chicken pox. Many surviving Native Americans put two and two together and realized that if they ran away from the Spanish, they could not kill them with their air.

5. Cruelty and thievery of the Spanish. The Aztecs and all the other tribes of North and South America could not comprehend or compete with the cruelty and thievery of the Spanish. The European wonder lust for gold and riches could not be impeded. Spanish conquistadors would kill, torture, rape, steal, and burn to obtain riches. The two main reasons were religion and social placement.
Religion: Christianity in Europe for all of its forgiveness and Christ like living did not hold a very tolerant view of people outside the faith. Muslims and Jews were the exception, but the religions of Africa and the Americas were seen as a joke. These people did not have souls. Since they did not have souls, killing one of these people was not seen as all that bad. It was not like squashing a bug, but very few Europeans wept for the deaths of Africans and American Indians.

Social Placement: To understand what I mean by this, you have to understand who exactly was a conquistador. Men that came over to the Americas were independent men with no family ties.  They did not value life for Christian people let alone Africans and American Indians. So, when you combine these two, Spanish conquistadors had no problem killing mercilessly.

6. Fighting styles. The fighting styles of the two cultures were in completely opposite. As you can see from the previous point, Spanish had no reservations fighting to kill. The Aztecs however, were a little different. A soldier raised his status in society by capturing the enemy. Aztec religion called for blood for their gods. This blood came from sacrifice. Captured people did well. So, if one culture is purely trained to "shoot to kill," and the other culture is trained to "shoot to capture," the killer culture will win more times than they lose.

7. Treaties with minor tribes. Cortez found out that the tribes on the outer rim of the Aztec empire hated the Aztecs. The constant need for sacrifice, materials, and other taxes made them more than willing to aid the Spanish. Cortez of course promised these tribes the ability to rule themselves and re obtain their riches that were taken by the Aztecs. Of course, once Cortez got rid of the Aztecs he turned his sights on the minor tribes and destroyed them too.