It was believe that the Nahua people began to migrate from northern Mexico to Mesoamerica in the 6th century. They began populating the places of central Mexico. The Nahua people merged with the complex civilizations of Mesoamerica. They adopted some religious and cultural belief and practices resulting to the foundation of the later Aztec culture. They raised to power during the post-classical period at such sites as Tula, Hidalgo. The Nahua power center was in Azcapotzalco in the 12th century,from where the Tepanics dominated the Mexican Valley. In this time,tribe of Mexica arrive in the central Mexico.(software media)

The origin of the Mexica tribe came from uncertain story. They came from Aztlan according to the legend. It was thought that this place was located somewhere to the north valley of Mexico. Some Historians and experts locate this place somewhere in the far north in the Southwestern United States.

The Mexica reportedly arrived in the place of Chapultepec in or around 1248. On that time, the valley of Mexico had already many city-states.The two most powerful of these city-states are the Culhuacan in the Southern part and Azcapotzalco on the west. The inhabitants of Azcapotzalco, the Tepanecs soon expelled the Mexicas from Chapultepec. In the year 1299, Cocoxtli, the Culhuacan ruler gave permission for the Mexicas to settle in the empty barrens of Tizapan.

In the year 1323 according to stories the Mexicas were shown a vision. It is a vision of an eagle perched on a pricky pear cactus and eating a snake. These vision indicates that this location is the right place for the Mexicas to build their homes. Eventually, the Mexicas was said to arrived on a small island in  Lake Texcoco and founded the town of Tenochtitlan in the year 1325. It was the year 1376 when the Mexicas elected their first Huey Tlatoani,Acamapichtli,who is living in Texcoco at the time. Within 50 years, The Mexica becomes a tributary of Azcapotzalco. Azcapotzalco become a regional power.

When Maxta, son of Tezozomoc assasinated Chimalpopoca (the Mexican ruler), the triple alliance between the places of Tenochtitlan,Texzcoco, and vil emerged. To be able to defeat Maxtla, Itzcoatl the successor of the Mexica ruler who was assassinated,allied with the exiled ruler of Texcoco, Nezahuallcoyotl. Their coalition became the foundation of the Aztec triple Alliance that eventually defeated Azcapotzalco.

This triple alliance flourished and in the next 100 years, dominate the valley of Mexico and was able to extend power to the Gulf of Mexico and the shores of the Pacific. Eventually,Tinochtitlan became the dominant power beteween the three allied.

Tlacaelel and Montezuma I, the two nephews of Itzcoatl was considered to be architects of the Aztec empires. In 1440, Montezuma I succeeded Itzcoatl as Hueyi Tlatoani.Tlacaelel was also offered to be Tlatoani but he preferred to be behind the throne and power of Montezuma I. Tlacealel was able to reformed the Aztec state and religion.

Based on some sources,Tlacaelel ordered the burning of most of the Aztec books and he claims that the books contains lies. He rewrote the history of the Aztec of the Aztec people. The writings where put to the curriculum that is taught to the scholars. It promotes and projects the idea and belief that the Aztecs were a powerful and mythical people and nation,thus forgetting a possible true history of their humble origin and beginning. A component of this reform includes then institution of the ritual war or the flower war,a way to have trained warriors. It also created the necessity to offer constant sacrifices to keep the movement of the sun.