The Aztecs entered the Valley of Mexico as poor travelers about 1300 A.D. They had to explore out an uncertain survival by allying themselves with more strong families in the area. They ultimately resided on a muddy island in the Lake. So the Aztecs were neglected to develop their island and a city upon it. During the Aztec period, Mexico City was originally developed over a lake, the Lago de Texcoco. Aztecs developed an unnatural island by depositing soil into the lake. Later, the Spaniards constructed a second Mexico City atop the wastes of Tenochtitlán. Teotihuacán was established in 1325 A.D.
