Our chief concern, however, in groping our way through the tangled labyrinth of tradition, is to ascertain the story of the AZTECS, whose advent has been already announced. It was about the year 1160, that they departed from Aztlan, the original seat of their tribe, on their journey of southern emigration. Their pilgrimage seems to have been interrupted by numerous halts and delays, both on their route through the northern regions now comprehended in the modern Republic of Mexico, as well as in different parts of the Mexican valley which was subsequently to become their home and capital. At length, in 1325, they descried an eagle resting on a cactus which sprang from the crevice of a rock in the lake of Tezcoco, and grasping in his talons a writhing serpent. This had been designated by the Aztec oracles as the site of the home in which the tribe should rest after its long and weary migration; and, accordingly, the city of Tenochtitlan, was founded upon the sacred spot, and like another Venice rose from the bosom of the placid waters. It was near a hundred years after the founding of the city, and in the beginning of the fifteenth century, that the Tepanecs attacked the Tezcocan monarchy, as has been related in the previous part of this chapter. The Tezcocans and the Aztecs or Mexicans united to put down the power of the spoiler, and as a recompense for the important services of the allies, the supreme dominion of the territory of the royal house of Tezcoco was transferred to the Aztecs. The Tezcocan sovereigns thus became, in a measure, mediatized princes of the Mexican throne; and the two states, together with the neighboring small kingdom of Tlacopan, south of the lake of Chalco, formed an offensive and defensive league which was sustained with unwavering fidelity through all the wars and assaults which ensued during the succeeding century. The bold leaguers united in that spirit of plunder and conquest which characterizes a martial people, as soon as they are surrounded by the necessaries, comforts, and elegances of life in their own country, and whenever the increase of population begins to require a vent through which it may expand those energies that would destroy the state by rebellions or civil war, if pent up within the narrow limits of so small a realm as the valley of Mexico. Accordingly we find that the sway of this small tribe, which had but just nestled among the reeds, rocks and marshes of the lake, was quickly spread beyond the mountain barrier that hemmed in the valley. Like the Hollanders, they became great by the very wretchedness of their site, and the vigilant industry it enforced. The Aztec arms were triumphant throughout all the plains that swept downward towards the Atlantic, and, as we have seen, even maintained dominion on the shores of the Pacific, or penetrated, under the bloody Ahuitzotl, the remotest corners of Guatemala and Nicaragua.