Legend and history
The earliest part of the Mexica story is tradition, not documented history. Mexica sources, written down in the sixteenth century from older oral and pictorial records, say that their ancestors came from Aztlan, a place of origin whose location is unknown and may never have been a real place in the way the stories describe. The name Aztlan is the source of the word “Aztec”, although the people themselves used the name Mexica. The Mexica migration legend is therefore best read as a foundation story, shaped by later political needs. The firmer ground starts when the Mexica appear in the Valley of Mexico in the 1200s.
The migration story
In the traditional account, seven groups left a place of origin sometimes pictured as Chicomoztoc, the “seven caves”. The Mexica were guided by their patron god Huitzilopochtli, who told them to keep moving until they found a sign. The route, shown in manuscripts such as the Codex Boturini, is a sequence of stops where they stayed for years before moving again. Many places on it can be matched to real sites in central Mexico, but the early stages cannot be traced.
Every culture has similar origin tales. Compare the Carthage founding legend, which tells how Dido led settlers from Tyre; such accounts explain why a people belong where they are, and may contain only a small historical core.
Arrival in the Valley of Mexico
By the 1200s the best farmland around the lakes was already held by established city-states. The Mexica were treated as newcomers, and several accounts describe them as unwelcome. They lived for a time near Chapultepec, were defeated by neighbours and then served the ruler of Culhuacan as warriors. A famous episode, which accounts tell with variations, ended with a break between the Mexica and Culhuacan, after which they were again forced to move.
Founding Tenochtitlan, around 1325
The Mexica came to rest on a small island in Lake Texcoco. In the tradition, they saw an eagle perched on a prickly pear cactus, the sign Huitzilopochtli had promised. The date given is 1325, an approximation derived from native annals and not from radiocarbon dating or other direct archaeological evidence. The image of the eagle, the cactus and a snake is now on the Mexican flag.
The first rulers were linked to the older Culhuacan dynasty, which gave the new city a respectable lineage. A second Mexica settlement, Tlatelolco, was founded nearby. For about a century the Mexica were vassals of Azcapotzalco, serving as fighters and paying tribute.
From vassal to empire, 1428 onward
Around 1428 Tenochtitlan joined Texcoco and Tlacopan against Azcapotzalco, and the victors formed the Triple Alliance. The key stages of the expansion that followed were these: Itzcoatl began the rise, Moctezuma I extended control to the Gulf Coast and southward, and later rulers pushed into Oaxaca and the Pacific coast. Ahuitzotl (ruled from 1486 until about 1502) is remembered for the dedication of the enlarged Templo Mayor in 1487 and for campaigns far to the south.
This growth happened at almost the same time as the Pachacuti expansion of the Inca, in the same century, although the two empires had no contact. Both were young states by the time Europeans arrived. The Aztec state was also many centuries removed from the Classic Maya collapse and from the age of the Olmec civilization, and drew on the long record of earlier Mesoamerican culture.
Moctezuma II and the years before the Spanish
Moctezuma II became ruler in 1502. He is described as a priest-king who strengthened the distance between nobles and commoners, and he continued to campaign. Tension within the empire grew: rebellions occurred, and Tlaxcala remained independent. Omens described in later sources, including comets and a strange light in the sky, are usually regarded by historians as stories added after the conquest to explain it.
1519 to 1521
The arrival of Hernan Cortes in 1519 set off events that ended the empire in two years. Moctezuma was taken captive, died in 1520, and was succeeded by Cuitlahuac and then Cuauhtemoc. Tenochtitlan fell on 13 August 1521 after a siege. The Spanish conquest of Yucatan, against Maya cities, took much longer and followed a different path.
What came after
The Spanish founded Mexico City on the ruins and ruled through the colony of New Spain, while some Nahua nobles kept positions of local authority for a time. Nahua writers and artists produced histories in the decades after the fall, which is why we know the migration tradition at all. The Nahuatl language and many customs survived, and millions of people in Mexico today are of Nahua descent.