The Aztec version of the legend is best known and describes a mythical land known as Aztlán where a sacred cave called Chicomostoc (place of the seven caves) was found. Each cave was home to a tribe with a common ancestry, and from here they began an exodus to the lands to the south.
The Mexica (Aztec) believed themselves to be the last to leave and their calendar began on the date they left, the 24th May, 1024AD. When they arrived in the southern lands, the other tribes already occupied all the available lands. So they led a nomadic life until they finally saw the prophesied vision of an eagle perched upon a cactus with a serpent in its beak. It was here that they settled, on the banks of Lake Texcoco, and built the mighty city of Tenochtitlan.
There is no certainty as to whom the “Seven Tribes” were. Many legends speak of the Seven Caves and include different tribes. The most popular theory is that the seven tribes are the Nahuatl speaking cultures who settled in central Mexico. These are the: Xochimilca, Tlahuica, Acolhua, Tlaxcalan, Tepaneca, Chalca, and Mexica.
However, other non-Nahuatl speaking groups, such as the Matlatzinca, also believed themselves to have originated at Chicomoztoc. Many attempts have been made to identify the location of Chicomoztoc, but there is no certainty as to where it was. Many historians believe it is simply a legend designed to manipulate warring tribes into (re)uniting as a single Aztec Empire.
The concept of caves being the birthplace of mankind stretches way beyond the 11th century and spans the majority of cultures across Mesoamerica. The likelihood is that these mystic caves were believed to the wombs of the earth – and a 16th century book called the “Historia Tolteca-Chichimeca” alludes to this association by representing Chicomostoc as a womb-like entity, complete with vaginal passage. Although the book was written during the Colonial period, its author, Fernando de Alva Cortés Ixtlilxochitl, was the great-great-grandson of the penultimate Aztec ruler, Cuitláhuac, and an ancestor of Ixtlilxochitl I and Ixtlilxochitl II, who were both rulers of Texcoco – so he had authority and knowledge of pre-Hispanic customs and legends.
Mesoamerican myths and legends often combined historical events with a cosmological events to leave a record of when the event happened and a permanent memorial to the event in the heavens. The most likely cosmological representation of the seven tribes/caves is the Pleiades. The timing of the supposed exodus would probably coincide with a cosmic event that involved this cluster of seven stars.
The most probable geographical location is thought to be El Cerro de Culiacán, Guanajuato, where there is evidence of a convergence of cultures. However, the depiction in the “Historia Tolteca-Chichimeca” features a crooked mountain above the caves, which was the emblem of Culhuacan, a key city in pre-Hispanic Mexico.
Another theory is that the crooked hill combined with the desert-like sandy ground, thistles and cacti, is symbolic of La Quemada, a city whose origin is deeply mysterious and whose demise coincides with the time of the exodus.