The whole story of the conquest of Spanish North America is coloured by the genius of its greatest hero, Hernán Cortés. Every conquistador sought to emulate Cortes in his meteoric rise to fame. None equalled him in his diversity of talents—his military ability; his capacity for retaining the loyalty not only of his own men, but of his conquered foes; his skill in placating and reassuring Charles V, that most jealous of monarchs.

Cortés's defeat of the Aztec confederacy, however, and his capture of the capital city of Tenochtitlán-Mexico in 1521, marked only the beginning of the conquest of New Spain. West of Anahuac, the Mexico of the Aztecs, were great mountain ranges, their valleys inhabited by independent peoples speaking alien tongues. Beyond them lay the South Sea and the way to China. To the north were endless barren hills; beyond the hills, deserts; and beyond the deserts another region inhabited by settled villagedwellers. Native rumours of these northern pueblos gave rise, in the Spanish imagination, to golden tales of Gran Quivira and Cibola of the Seven Cities.

Most of the area of northern Mexico (the name being used, for the moment, in its modern sense) is a high table-land, becoming less elevated, less broken, and progressively more arid towards the north. The table-land is bounded on the west by a chain of high mountains—the Sierra Madre Occidental—some hundred miles wide and running north and south.