As an undergraduate, my major was Anthropology and Spanish. I identify as an anthropologist and I am trained as such. As a student of anthropology, I focused on the indigenous groups of Mesoamerica. As a student of Spanish literature, I became intrigued by the literature of Mexican authors and the cosmology of Mesoamerica, this interest greatly facilitated by the efforts of Dr. Carlos Vento, professor of literature within the department of Spanish and Portuguese at the University of Texas at Austin.
One lesson we learned in those days was that the Aztec-Mexico, who founded the city of Tenochtitlan in 1325, came upon Teotihuacan as they wandered the Valley of Mexico searching for a location to settle within the valley. As it turned out for the Aztec-Mexica, the most suitable land within the valley was already occupied by other indigenous groups. The Aztec-Mexica settled for an uninhabited island in the middle of Lake Texcoco, or so the story goes. Later the Aztec-Mexica incorporated this settlement story into their creation history. It was prophesied that the Aztec-Mexica would wander until the they found an eagle devouring a snake while sitting on a cactus in the middle of an island. The Aztec-Mexica creation story became the foundation legend for the settling of what became Mexico City, whose vision is immortalized on the Mexican flag today. According Dr. Vento, the Aztec-Mexica found a way to legitimate their presence in the Valley of Mexico, having been relegated to the least inhabitable lands. The Aztec-Mexica however made the most of it through the creation of chinampa agriculture in which fertile soil was piled up creating mounds upon which crops could be produced. Examples of this type of agriculture can be found today in the Mexico City community of Xochimilco (link).
This agriculture system proved effective because it allowed for several crops to be harvested annually. This production allowed the Aztec-Mexica to become a formidable power within the Valley of Mexico and beyond as they established Tenochtitlan, ultimately becoming a center of trade in agriculture products and more. The success of the Aztec-Mexica in Tenochtitlan allowed for the consolidation of power and made them less than popular as their control and demand for tribute expanded through the Valley of Mexico and beyond to locations as far as Guatemala in the south and East and beyond to the modern states of Michoacán and Jalisco to the west. The lack of support from the indigenous groups throughout what became Mexico proved fatal during the Spanish conquest when support for the Aztec-Mexica city of Tenochtitlan did not materialize when needed and the Aztec city fell to the Spanish invaders.