The Founding of Tenochtitlan and the Origin of the Aztecs

Tula, Hidalgo, Mexico under a blue sky.
The ruins of the Toltec site Tula were one of the ancient archaeological sites in the Basin of Mexico that awed the arriving Mexica and inspired their growth into the Aztec Empire. Travel Ink / Getty Images

The origins of the Aztec Empire are part legend, part archaeological, and historical fact. When the Spanish conquistador Hernán Cortés arrived in the Basin of Mexico in 1517, he found that the Aztec Triple Alliance (a strong political, economic, and military pact) controlled the Basin and much of Central America. But where did they come from and how did they get to be so powerful?

Where Did the Aztecs Come From?

The Aztecs, or more properly, the Mexica, as they called themselves, were not originally from the Valley of Mexico. Rather, they migrated from the north. They called their homeland Aztlan, "the Place of Herons." Aztlan has not been identified archaeologically and was likely at least partly mythical. According to their own records, the Mexica and other tribes were known as the Chichimeca. They left their homes in northern Mexico and the southwestern U.S. because of a terrible drought. This story is told in several surviving codices (painted, folding books), in which the Mexica are shown carrying with them the idol of their patron deity Huitzilopochtli. After two centuries of migration, around 1250, the Mexica arrived in the Valley of Mexico.

Today, the Basin of Mexico is filled with the sprawling metropolis of Mexico City. Underneath the modern streets are the ruins of Tenochtitlán, the site where the Mexica settled. It was the capital city of the Aztec empire.

Basin of Mexico Before the Aztecs

When the Aztecs arrived in the Valley of Mexico, it was far from an empty place. Because of its wealth of natural resources, the valley has been continuously occupied for thousands of years. The first known substantial occupation is established at least as early as 200 BCE. The Valley of Mexico lies 2,100 meters (7,000 feet) above sea level and it is surrounded by high mountains, some of which are active volcanoes. Water coursing down in streams from these mountains created a series of shallow, marshy lakes that provided a rich source for animals and fish, plants, salt, and water for cultivation.

Today, the Valley of Mexico is almost entirely covered by the monstrous expansion of Mexico City. There were ancient ruins as well as thriving communities here when the Aztecs arrived, including the abandoned stone structures of two major cities: Teotihuacan and Tula, both referred to by the Aztecs as "the Tollans."

  • Teotihuacán: Almost 1,000 years before the Aztecs, the huge and carefully planned city of Teotihuacán (occupied between 200 BCE and 750 CE) flourished there. Today, Teotihuacan is a popular archaeological site a few miles north of modern Mexico City that attracts thousands of tourists each year. The word Teotihuacán comes from Nahuatl (the language spoken by the Aztecs). It means "The Birthplace of the Gods." We don't know its real name. The Aztecs gave this name to the city because it was a sacred place associated with the legendary origins of the world.
  • Tula: Another city that developed in the Valley of Mexico before the Aztecs is Tula, the early post-classic capital of the Toltecs between 950 and 1150. The Toltecs were considered by the Aztecs to be the ideal rulers, brave warriors who excelled in the arts and sciences. Tula was so revered by the Aztecs that the king Motecuhzoma (Montezuma) sent people to dig up Toltec objects for use in the temples at Tenochtitlán.

The Mexica were awestruck by the massive structures built by the Tollans, considering Teotihuacan to be the sacred setting for the creation of the current world. or Fifth Sun. The Aztecs carried away and reused objects from the sites. More than 40 Teotihuacan-style objects have been found in offerings within Tenochtitlan's ceremonial precinct.

Aztec Arrival in Tenochtitlán

When the Mexica arrived in the Valley of Mexico in about 1200, both Teotihuacán and Tula had been abandoned for centuries but other groups were already settled on the best land. These were groups of Chichimecs, related to the Mexica, who had migrated from the north in earlier times. The late-coming Mexica were forced to settle on the inhospitable hill of Chapultepec or Grasshopper Hill. There, they became vassals of the city of Culhuacan, a prestigious city whose rulers were considered the heirs of the Toltecs.

As acknowledgment for their assistance in battle, the Mexica were given one of the daughters of the King of Culhuacan to be worshiped as a goddess/priestess. When the king arrived to attend the ceremony, he found one of the Mexica priests dressed in the flayed skin of his daughter. The Mexica reported to the king that their God Huitzilopochtli had asked for the sacrifice of the princess.

The sacrifice and flaying of the Culhua Princess provoked a ferocious battle, which the Mexica lost. They were forced to leave Chapultepec and move to the marshy islands in the middle of the lake.

Founding of Tenochtitlan

After they were forced out of Chapultepec, according to the Mexica myth, the Aztecs wandered for weeks in search of a place to settle. Huitzilopochtli appeared to the Mexica leaders and indicated a place where a great eagle was perched on a cactus killing a snake. This place, smack dab in the middle of a marsh with no proper ground at all, was where the Mexica founded their capital Tenochtitlán. The year was 2 Calli (Two House) in the Aztec calendar, which translates in our modern calendar to 1325.

The apparently unfortunate position of their city, in the middle of a marsh, actually facilitated economic connections and protected Tenochtitlán from military attacks by restricting access to the site by canoe or boat traffic. Tenochtitlán grew rapidly as both a commercial and military center. The Mexica were skillful and fierce soldiers and, despite the story of the Culhua princess, they were also able politicians who created solid alliances with the surrounding cities.

Growing a Home in the Basin

The city grew rapidly, filling up with palaces and well-organized residential areas and aqueducts providing fresh water to the city from the mountains. At the center of the city stood the sacred precinct with ball courts, schools for nobles, and priests' quarters. The ceremonial heart of the city and of the whole empire was the Great Temple of Mexico-Tenochtitlán, known as the Templo Mayor or Huey Teocalli (the Great House of the Gods). This was a stepped pyramid with a double temple on top dedicated to Huitzilopochtli and Tlaloc, the main deities of the Aztecs.

The temple, decorated with bright colors, was rebuilt many times during Aztec history. The seventh and final version was seen and described by Hernán Cortés and the conquistadors. When Cortés and his soldiers entered the Aztec capital on November 8, 1519, they found one of the largest cities in the world.


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Maestri, Nicoletta. "The Founding of Tenochtitlan and the Origin of the Aztecs." ThoughtCo, Dec. 13, 2020, Maestri, Nicoletta. (2020, December 13). The Founding of Tenochtitlan and the Origin of the Aztecs. Retrieved from Maestri, Nicoletta. "The Founding of Tenochtitlan and the Origin of the Aztecs." ThoughtCo. (accessed March 26, 2023).