According to their first records, the Aztecs, or Mexica, originally lived to the north of the Valley of Mexico, partially under the control of the Toltec empire. Driven to leave by the pressure of their Toltec oppressors, who demanded huge tributes from the farming Aztecs, the Aztecs fled from their home city of Aztlan. After settling in and being evicted from various different areas, the Aztecs settled in Tizapan at the relative center of present-day Mexico. These lands were then under the yoke of the Culhuacan, and the Aztecs were allowed to stay on the land only if they became tributaries, the equivalent of European vassals.
Shortly after, war broke out between the Aztecs and Culhuacan, and the Aztecs were routed. Fleeing once again, they eventually settled in the land of the Tepanec and became King Tezozomoc's vassals. The land on which they were allowed to settle was a group of islands in the center of Lake Texcoco.
On one of these islands the Aztecs founded the sacred city of Tenochtitlan and immediately built an altar to their patron god, Huitzilopochtli, God of War. As the city grew, a splinter group broke off and settled on a neighboring island, founding the city of Tlatelolco. The two cities eventually merged with Tlatelolco becoming the trading center and Tenochtitlan becoming the political and religious capital.
The Mexican nation steadily rose in power but remained under the yoke of the Tepanec until the king Itzcoatl (reigned 1427-1440) formed a military alliance with nearby Texcoco and other neighboring groups and forced the Tepanec out. Under the rule of Itzcoatl, and for eighty years afterwards, the Aztecs proceeded to subjugate the remainder of the Valley of Mexico and then further beyond--from the Pacific Ocean in the west to the Gulf coast in the...