Like the pre-Hispanic villages of Xochimilco and Tláhuac, Iztapalapa began as a village on the shores of the lake system and dedicated to farming on chinampas. The first settlements on this side of Lake Texcoco were formed by refugees from the fall of Teotihuacan at the base of the Cerro de Culhuacán hill. These people were led by a chief named Mixcoatl and would become known as the Culhuas. At that time, the area was a peninsula jutting onto the lake formed by the Sierra de Santa Catarina. The first city on this peninsula was Culhuacán on the south side next to the Cerro de la Estrella, which grew to contain various neighborhoods surrounded by chinampas, or artificial islands in the lake used to grow food. These and the exploitation of lake resources was the basis of the city's economy.