themselves adopted it; and in the invaded districts there remained groups and nuclei of Nahua populations who maintained its principles, its arts and its spirit, to which their conquerors readily conformed. The last conquerors had been established as masters in the Mexican district for more than a century when the Spaniards arrived there. They were the Aztecs. They had conquered or shattered what was called the Chichimec empire, which in its turn had destroyed, some centuries earlier, the Toltec empire. But it would be a mistake to think of three successive empires, Toltec, Chichimec and Aztec, one supplanting the other in the same way as the Frankish empire, for example, took the place of that of Rome, which in its turn had replaced divers others more ancient yet. What really took place was what follows.
The prolonged migrations of the Nahuas towards the North had not spread civilization uniformly amongst all the tribes encountered on the route. Thus, down to the sixteenth century, there still existed in the heart of Mexico tribes very little removed from the savage state, such as the Otomis
