A diametrically opposed theory is that Casas Grandes was established by the elites of the Ancestral Puebloans from the north who were leaving Chaco Canyon and other areas during their decline. The third theory is that Casas Grandes is purely a local creation, a community that grew over time to dominate its region and adopted some religious and social customs from the civilizations of Mesoamerica. There is common academic agreement that trading existed between the cultures of Mesoamerica, Aridoamerica, and the American southwest, though not on a large or planned scale. As no system like the pochteca existed in the north, the architectural remains throughout yet share a commonality of knowledge from north to south, that included such ancient population centers such as at Snaketown. Casas Grandes was abandoned in about 1450. It is unclear whether it was abandoned slowly over a period of years or quickly. The Spanish explorer Francisco de Ibarra found the site of Casa Grandes in 1565. The Indians nearby, non-agricultural nomads, probably Suma or Jano, told him that a war with village dwellers, the Opata, four days journey west had caused the abandonment of Casas Grandes and that the inhabitants had moved six days journey north. This story suggests the people of Casas Grandes joined the Pueblos on the Rio Grande in New Mexico. Other theories are that the Casas Grandes people migrated west to Sonora and joined or became the Opata whom the Spaniards found in the mid 16th century living in "statelets," small but well-organized city states. It is also possible that Casas Grandes was abandoned because opportunities were greater elsewhere. Other communities in the Southwest are known to have been abandoned in favor of a new home. The language the inhabitants of Casas Grandes spoke is unknown. Given the Mesoamerican influence on Casas Grandes, Nahuatl was probably widely spoken but it was not the primary language of the people.