Then was formed that remarkable league, which, indeed, has no parallel in history. It was agreed between the states of Mexico, Tezcuco, and the neighboring little kingdom of Tlacopan, that they should mutually support each other in their wars, offensive and defensive, and that in the distribution of the spoil one-fifth should be assigned to Tlacopan, and the remainder be divided, in what proportions is uncertain, between the other powers. The Tezcucan writers claim an equal share for their nation with the Aztecs. But this does not seem to be warranted by the immense increase of territory subsequently appropriated by the latter. And we may account for any advantage conceded to them by the treaty, on the supposition that, however inferior they may have been originally, they were, at the time of making it, in a more prosperous condition than their allies, broken and dispirited by long oppression. What is more extraordinary than the treaty itself, however, is the fidelity with which it was maintained. During a century of uninterrupted warfare that ensued, no instance occurred where the parties quarrelled over the division of the spoil, which so often makes shipwreck of similar confederacies among civilized states.25
The allies for some time found sufficient occupation for their arms in their own valley; but they soon overleaped its rocky ramparts, and by the middle of the fifteenth century, under the first Montezuma, had spread down the sides of the table-land to the borders of the Gulf of Mexico. Tenochtitlan, the Aztec capital, gave evidence of the public prosperity. Its frail tenements were supplanted by solid structures of stone and lime. Its population rapidly increased. Its old feuds were healed. The citizens who had seceded were again brought under a common government with the main body, and the quarter they occupied was permanently connected with the parent city; the dimensions of which, covering the same ground, were much larger than those of the modern capital of Mexico.26
Fortunately, the throne was filled by a succession of able princes, who knew how to profit by their enlarged resources and by the martial