Final answer:
The Mexica, also known as Aztecs, originated from Aztlán and established Tenochtitlan in Lake Texcoco, which became the Aztec Empire's capital. After forming a Triple Alliance with Texcoco and Tlacopan, they expanded their empire throughout Mesoamerica until the Spanish conquest in 1521.
Step-by-step explanation:
The Mexica were the indigenous people who founded Tenochtitlan, which later became the capital of the Aztec Empire. Originating from a mythical homeland called Aztlán, somewhere in northern Mexico, the Mexica were part of the Nahuatl-speaking communities. On their journey south, they settled in various locations before arriving in the Valley of Mexico. After allying themselves with several city-states and engaging as mercenaries, the Mexica eventually established Tenochtitlan in 1325 on an island in Lake Texcoco.
Following turbulent alliances and political shifts, a new leadership in Tenochtitlan formed a Triple Alliance with Texcoco and Tlacopan around 1428. This alliance, engaged in shared military campaigns and taxation policies, marked the beginnings of the Aztec Empire. The Mexica, under leaders like Moctezuma I, expanded their territory significantly through diplomacy, tribute collection, and when necessary, warfare. As the empire grew, Tenochtitlan became a hub of trade, culture, and religion, boasting a population of around 100,000 before the Spanish conquest led by Cortés in 1521.