A collective name applied to various barbarian tribes who invaded the valley of central Mexico from the northwest from c 7th-13th century AD in periodic waves and migrations. The Aztec, or Mexica, were one of the competing Chichimec tribes. Some of these groups, who may have been farmers, may have entered the Valley of Mexico after the fall of Teotihuacán, and there is a Chicimec constituent in Toltec culture. The Chichimec period proper, however, begins after the destruction of Tula and the decline of Toltec influence in about 1200 AD. In 1224, a band of Náhuatl-speaking Chichimecs entered the northern part of the Valley and established a kingdom at Tenayuca. After their arrival the barbarians settled down again to farming life, became civilized, and were eventually absorbed into the Aztec confederation. In the north, some independent Chichimecs maintained their nomadic and hunting way of life until the Spanish conquest. The Chichimecs are also associated with the introduction of the bow and arrow into the Valley of Mexico. Their language, also called Chichimec, is of the Oto-Pamean language stock.