The Mexica (Nahuatl: Mēxihkah, meːˈʃiʔkaʔ; singular Mēxihkatl) were a Nahuatl-speaking people of the Valley of Mexico who were the rulers of the Mexica Empire. The Mexica established Tenochtitlan, a settlement on an island in Lake Texcoco, in 1325. A dissident group in Tenochtitlan separated and founded the settlement of Tlatelolco with its own dynastic lineage. In 1521, they were conquered by an alliance of Spanish conquistadors and indigenous people including the Tlaxcaltecs led by Hernán Cortés.
The Mexica are eponymous of the place name Mexico (Mēxihco meːˈʃiʔkoˀ), originally referring to the interconnected settlements in the valley that is now Mexico City. The group was also known as the Culhua-Mexica in recognition of its kinship alliance with the neighboring Culhua, descendants of the revered
Toltecs, who occupied the Toltec capital of Tula from the 10th to 2nd centuries. The Mexica of Tenochtitlan were additionally referred to as the "Tenochca," a term associated with the name of their altepetl (city-state), Tenochtitlan, and Tenochtitlan's founding leader, Tenoch.
The name Aztec was coined by Alexander von Humboldt, who combined Aztlán ("place of the heron"), their mythic homeland, and tec(atl) "people of".
The term "Aztec" often today refers exclusively to the Mexica people of Tenochtitlan, Mēxihcah Tenochcah, a tribal designation referring only to the Mexica of Tenochtitlan, excluding those of Tlatelolco or cōlhuah. The term Aztec is often used very broadly to refer not only to the Mexica, but also to the Nahuatl-speaking peoples of the Valley of Mexico and neighboring regions.
After the decline of the Toltecs, about 1200 CE, various Nahua-speaking nomadic peoples entered the Valley of Mexico, possibly all from Aztlan, whose location is unknown. The Mexica were the last group to arrive. There they "encountered the remnants of the Toltec empire (Hicks 2008; Weaver 1972)." According to legend, the Mexica were searching for a sign which one of their main gods, Huitzilopochtli, had given them.