The Aztec Empire, sometimes known as the Triple Alliance, was formed in 1428 because of an alliance between three smaller nations: The Tenochtitlan, Texcoco, and Tlacopan. It was formed in 1428, and collapsed in 1521 when its capital, Tenochtitlan, fell to the Spanish Conquistador Hernān Cortēs. The Aztecs were known for their gold, cool pyramids, and human sacrifices to their gods.
Why It Was Formed
The Aztec Empire was formed because three smaller nations, the Tenochtitlan, Texcoco, and Tlacopan (that’s fun to say, Tlacopan, Tlacopan, Tlacopan) formed an alliance. They formed an alliance because another nation, the Azcapotzalco, was very powerful and demanded heavy tribute from the other nations in the area. Because of this mutual hate for the Azcapotzalco, as well as the economic and strategic benefits, they created the alliance.
What it led to
The Triple Alliance’s formation led to the fall of the Azcapotzalco Empire, as the combined strength of all three members of the alliance was far greater than that of its enemy. It also led to the creation of the Aztec Empire, when all three nations rapidly expanded their territory and influence. Their collaboration was possibly the best thing all three nations could have done.
The Battle of Otumba
On July 8, 1520, Spanish Conquistadors under the command of Hernān Cortēs fought against Triple Alliance forces. Hernān Cortēs with his army of Spanish soldiers and Native American allies, marched toward the major Aztec city of Otumba, which was along the path his army was taking. Spanish scouts told him of a large Aztec army in a valley not far ahead.
Cortēs and his allies were retreating to Tlascala, the homeland of his supporters. Unfortunately for the Spaniards, Hernān Cortēs himself had received a wound to his head. Also bad for the Spanish, they were very low on water and supplies and had lost a lot of soldiers.
Hernān Cortēs was implementing strict discipline on his men. He even made the wounded carry their own weight, as the horses were very tired. Also, he marched around the populated areas of the Aztec Empire, and after a week of marching he was less than a straight 2 day march from where they had started.
As for the Aztec army, they were much larger. They had almost 250,000 soldiers, almost 50 times the Spanish. However, the Aztecs did not have the supplies necessary for long wars. Their capital was consuming more than it produced (In fact, the city produced almost no supplies).
Each Aztec soldier had to pay for and carry his own supplies. They had no animals to carry their supplies. Wealthy warriors often hired servants to carry their things, but most soldiers could not afford to do that.
Sometimes, the government arranged for markets to be set up along the route so that soldiers could buy supplies. The Aztecs also did not develop tactics, due to war to them being ceremonial. Their wars were usually very short, and now, fighting against the Spanish for many years, their morale and economy were both falling.
Traditionally, Aztec battles were decided by numbers, and not much else. Because of this, the Aztec leader was planning on destroying the tiny Spanish army. Had Cortēs been less experienced, it probably would have spelled the end for the Spanish conquest.
In the start of the battle, Spanish soldiers using cannons fired upon a charging Aztec group. The Aztecs threw leaves and dust into the air, and continued to charge. The Spanish barely won the engagement by their skill and discipline in hand-to-hand combat.
During the battle, Cortēs decided to use his 20 horses to flank the main Aztec army, while his main force charged forward. The Aztec reserves rushed to the battle, but made little difference. The Aztecs tried to make a bigger flank around the Spanish cavalry, however failed.
Near the end of the battle, the Aztec force had been split into a large number of little groups, and their leader killed. The remaining Aztec force retreated. In the end, the Aztecs lost nearly 20,000 soldiers, while the Spanish lost 20-30 men, with unknown numbers from their Mexican allies.
The Fall of the Aztecs
Not long after Otumba, the Spanish captured the Aztec capital of Tenochtitlan, and the Triple Alliance collapsed. The city was burnt down, and in its ashes the Spanish built Mexico City. The surviving Aztecs were enslaved, and the Aztec Empire was no more.
Timeline of the Triple Alliance
- The Triple Alliance is formed
- The Aztec Empire is formed
- The Azcapotzalco Empire falls to the Aztecs
- La Noche Triste (The Sad Night)
- The Battle of Otumba
- The Aztec Empire falls

Modern day flag of Mexico. The Aztecs used symbols like the eagle and serpent shown on this flag
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Good job!
You’re right. Tlacopan is fun to say! I’ve heard of Cortēs but never knew much about him. This was a very informative bit of history that I was previously unfamiliar with. Thanks for sharing!
You’re very welcome! I’m glad you enjoyed it and learned something from it!
Very interesting! I knew the name Hernan Cortēs, but I did not now much about him!