The general, and best received tradition that we possess upon the subject, declares that the original inhabitants of this beautiful valley came from the north; and that perhaps the earliest as well as the most conspicuous in the legends, were the Toltecs, who moved to the south before the end of the seventh century, and settled at Tollan or Tula, north of the Mexican valley, where extensive architectural remains were yet to be found at the period of the conquest. This spot seems to have gradually become the parent hive of civilization and advancement; but, after four centuries, during which they extended their sway over the whole of Anahuac, the Toltecs are alleged to have wasted away by famine, disease, and the slow desolation of unsuccessful wars. This occurred about the year 1051, as the Indian tradition relates,--and the few who escaped the ravages of death, departed for those more southern regions now known as Yucatan and Guatemala, in which we perhaps find the present remains of their civilization displayed in the temples, edifices and tombs of Palenque and Uxmal. During the next century these valleys and mountains were nearly desolate and bare of population, until a rude and altogether uncivilized tribe, known as the Chichimecas, came from Amaquemecan, in the north, and settled in villages among the ruins of their Toltec predecessors. After eight years, six other Indian tribes called Nahuatlacs arrived, and announced the approach of another band from the north, known as the Aztecs, who, soon afterwards, entered Anahuac. About this period the Acolhuans, who are said to have emigrated from Teoacolhucan, near the original territories of the Chichimecas, advanced into the valley and speedily allied themselves with their ancient neighbors. These tribes appear to have been the founders of the Tezcocan government and nation which was once assailed successfully by the Tepanecs, but was finally delivered from thraldom by the signal bravery and talents of the prince Nezahualcoyotl, who was heir of the crown, supported by his Mexican allies.