The forlorn condition of the new settlers was made still worse by domestic feuds. A part of the citizens seceded from the main body, and formed a separate community on the neighboring marshes. Thus divided, it was long before they could aspire to the acquisition of territory on the main land. They gradually increased, however, in numbers, and strengthened themselves yet more by various improvements in their polity and military discipline, while they established a reputation for courage as well as cruelty in war which made their name terrible throughout the Valley. In the early part of the fifteenth century, nearly a hundred years from the foundation of the city, an event took place which created an entire revolution in the circumstances and, to some extent, in the character of the Aztecs. This was the subversion of the Tezcucan monarchy by the Tepanecs, already noticed. When the oppressive conduct of the victors had at length aroused a spirit of resistance, its prince, Nezahualcoyotl, succeeded, after incredible perils and escapes, in mustering such a force as, with the aid of the Mexicans, placed him on a level with his enemies. In two successive battles, these were defeated with great slaughter, their chief slain, and their territory, by one of those sudden reverses which characterize the wars of petty states, passed into the hands of the conquerors. It was awarded to Mexico, in return for its important services.[36] 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.[37]