Aztec is a term used to refer to certain ethnic groups of central Mexico, particularly those groups who spoke the Nahuatl language and who achieved political and military dominance over large parts of Mesoamerica in the 14th, 15th and 16th centuries, a period referred to as the Late post-Classic period in Mesoamerican chronology. Often the term "Aztec" refers exclusively to the people of Tenochtitlan, situated on an island in Lake Texcoco, who called themselves Mexica Tenochca or Colhua-Mexica.