On the other hand, the mutual interpenetration of the activities of the two races, not only in the important cities, but also in the small towns, where the imported plants and seeds began to be cultivated together with those of the country, with the help of animals and working tools, also imported; and even in the distant exploits carried out by the Spaniards with the help of the Indians for the purpose of reconnaissance and conquest, he ensured that, from then on, the fusion of the opposing interests of the Spaniards and the Indians began. This already appeared, in the double Spanish and indigenous name, of various colonies, then founded, and of the neighborhoods of them. On the other hand Cortés had already tried, to ensure his conquest, to prevent that, even without the will or the awareness of the Indian prince, Cuauhtemotzin,

The expansion of the conquest began before ancient Mexico City was taken; and it began especially as a result of the military expeditions sent from Cortés to the south, in the territory which today forms the state of Morelos. Then he continued in the country of the Mixtecs and in Guatemala, through the work of Pietro de Alvarado; in the country of the Mixtecs, again, by Francesco de Orozco; in Yucatán and Campeche, with the Montejos; in Colima, in Coatzacoalcos and in Honduras, with Cristóbal de Olid. Cortés himself pushed NE in 1522 and 1523. to dispute the rich province of Pánuco with the governor Francesco de Garay: and in his passage, he conquered the fertile lands of Metztitlán. In 1535, he embarked in Acalpulco and, after landing in Baja California, founded the colony of La Paz.

According to Plus-Size-Tips, the great advance towards the north, which began with the terrible raids of Nuño de Guzmán, who seized the lands of Jalisco and continued beyond, was continued by Francesco Vazquez de Coronado. On behalf of the viceroy Antonio de Mendoza, he made from 1540 to 1542, a journey of exploration which, started from Compostela, the first capital in New Galicia, founded in 1535 by Nuño de Guzmán, continued through the Nayarit, Sinaloa, Sonora, the high hills of New Mexico and the eastern prairies of the Rocky Mountains as far as Kansas, while several of his companions were sent on other side expeditions, in one of which Cárdenas discovered the Gran Cañón. The expedition of Giovanni Rodríguez Cabrillo and Bartolomé Ferrelo, made in 1542, also by order of Viceroy Mendoza, reached up to 42 ° north latitude;

Meanwhile, explorers, missionaries, miners and shepherds proceeded rapidly from Mexico towards the interior of the territory. In 1548, Zacatecas was founded; in 1563, Durango; in the same year and the following, Francesco de Ibarra explored the mountains and mines of the Sierra Madre Occidental and arrived at Casas Grandes, after having performed many other acts of audacity. Thus opening the way to expeditions, Antonio de Espejo, a wealthy resident of Mexico, arrived in 1582 and in 1583 as far as New Mexico, of which the conquest and colonization, combined with the viceroy, the second Luigi de Velasco, was carried out by Giovanni de Oñate, who extended (1596-1608) the dominions of New Spain to New Mexico and Kansas, founding the first colonies there. Before and after these, New Spain also expanded to N. and NE. del Pánuco: in 1565, up to Saltillo; in 1590, up to Monclova. Afterwards, there was a pause: but in 1655 the march continued; and later, although a number of Indians were hostile, many others persistently called the missionaries, sending emissaries from the territory beyond the Río Bravo, to Saltillo, Parral, Guadalaiara and Mexico for this purpose. During the viceroyalty of the archbishop fra Payo Enríquez de Rivera, in 1674, Antonio Balcárcel Riva de Neira Sotomayor was entrusted with the conquest and the first works of colonization, who, with the help of the Coahuilteco Indians, advanced beyond the Río Bravo and it was possible to convince them that the hostilities of the various Indian tribes among themselves made them unsuitable for a life in common. Shortly thereafter, in 1680, the great uprising of the Zuñi took place in New Mexico. But the other Indians, three years later, they appeared several times in Paso del Norte to solicit the missionaries and establish relations with the conquerors: after which, the forward movement of New Spain through Texas was carried out by the field master Giovanni Domínguez de Mendoza and by various Franciscans; as also, from 1686 to 1690, by the governor of Coahuila, Alonso de León and Damiano Menzanet, of the College of Santa Cruz de Querétaro. Twenty-six years later, in 1716, the definitive occupation of Texas by the Spaniards and Mexicans marked the western limit of French Louisiana.

Meanwhile, at NO. the Jesuits had begun their missionary work in 1590. In 1644, they had 35 missions in Sinaloa and Sonora, and in 1687 Eusebio Chino arrived at Pimeria Alta and explored the country as far as Arizona and Baja California, uniting it with the Catholic Church and New Spain and opening it to the knowledge of Europeans.