In 1337, a group of dissident Mexica broke away from the Tenochca leadership in Tenochtitlan and founded Mexico-Tlatelolco on the northern portion of the island.

Tenochtitlan was closely tied with its sister city, which was largely dependent on the market of Tlatelolco, the most important site of commerce in the area.

Under Quauhtlatoa (1428–1460), the Tlatelolca conquered the city-state of Ahuilizapan (now Orizaba, Veracruz), and fought against the people of Chalco along with the Tenochca.

Regarding its marketplace, he wrote that the Spanish "were astonished at the number of people and the quantity of merchandise that it contained, and at the good order and control that was maintained, for we had never seen such a thing before."

During Cortés's siege of Tenochtitlan, the Mexica's would retreat to Tlatelolco and even achieve a successful ambush against the Spanish conquistadores and their allies but would ultimately fall along with the rest of the island to Spain.

[4] With Tlatelolco viewing themselves as an independent city state it was easier for them to conform with the Spanish as they took the side of the Spaniards because of their opposition to the Mexica.

In the twentieth and twenty-first centuries, archeological excavations have taken place at the Tlatelolco (archaeological site) in what is now part of Mexico City.