By the eighth century, there was a small culture in the Acapulco area, which would first be dominated by the Olmecs, then by a number of others during the pre-Hispanic period. In Acapulco bay itself, there were two Olmec sites, one by Playa Larga and the other on a hill known as El Guitarrón. Olmec influence caused the small spread-out villages here to coalesce into larger entities and build ceremonial centers. Later, Teotihuacan influence made its way here via Cuernavaca and Chilpancingo. Then Mayan influence arrived from the Isthmus of Tehuantepec and through what is now Oaxaca. This history is known through the archeological artifacts that have been found here, especially at Playa Hornos, Pie de la Cuesta and Tambuco. In the 11th century, new waves of migration of Nahuas and Coixas came through here. These people were the antecedents of the Aztecs. Acapulco formally became part of the Aztec Empire in 1486 during the reign of Ahuizotl. It was part of a tributary province called Tepecuacuilco, but control here was relatively unorganized.