Which the following was not apart of spain’s nothern frontier or the modern southwest

The history of Spain's missions in the American South and Southwest reveals much about Spain's strategy, contributions, and failures in these regions. The expeditions of Francisco Vázquez de Coronado (1540 –42) and Juan de Oñate (1598) convinced Spanish authorities that no wealthy Indian empires like that of the Aztecs were to be found north of Mexico. Consequently the Spanish came to view the northern frontier of their empire as a defensive barrier and as a place where pagan souls might be saved. In what are now the states of Florida, Texas, New Mexico, Arizona, and California, missions were founded to propagate the doctrines of the Roman Catholic church. To protect these missions as well as the mines and ranches of Mexico from attack from the north, the Spanish established presidios — fortified garrisons of troops.