their conquerors, were, by means of frequent military expeditions made to check outbreaking rebellion, kept nominally subject to the Aztecs during fifty years, more or less, preceding the coming of the Spaniards, paying their annual tribute with some regularity. Outside the rocky barriers of their valley, the Mexicans maintained their supremacy only by constant war; and even within the valley their sway was far from undisputed, since several tribes, notably the Chalcas on the southern lake, broke out in open rebellion whenever the imperial armies were elsewhere occupied.
The Aztec empire proper, not restricting it to its original seat in the valley of Mexico, nor including within its limits all the nations which were by the fortunes of war forced at one time or another to pay tribute, may then be said to have extended from the valley of Mexico and its immediate environs, over the territories comprised in the present States of Mexico (with its modern subdivisions of Hidalgo and Morelos), Puebla, southern Vera Cruz, and Guerrero. Of all the nations that occupied this territory, most of them, as I have said, were of one blood and language with their masters, and all, by their character and institutions, possessed in greater or less degree the Nahua culture. Of many of the multitudinous nations occupying the vast territory surrounding the valley of Mexico, nothing is known beyond their names and their likeness, near or remote, to the Aztecs. For a statement of their names and localities in detail, the reader is referred to the Tribal Boundaries following the chapter on the Central Mexicans in the first volume of this work. Let it be understood, therefore, that the description of Aztec institutions contained in this volume applies to all the nations of the empire as bounded above, except where special limitation is indicated; besides which it has a general application to a much wider region, in fact to the whole country north of the isthmus of Tehuantepec.
In this connection, and before attempting a description
