Mexico-Tenochtitlan  audio , commonly known as Tenochtitlan (Classical Nahuatl: Tenochtitlan /tenotʃˈtitɬan/) was an Aztec altepetl (city-state) located on an island in Lake Texcoco, in the Valley of Mexico. Founded in 1325, it became the capital of the expanding Mexican Empire in the 15th century, until captured by the Spanish in 1521. At its peak, it was the largest city in the Pre-Columbian Americas. When paired with Mexico, the name is a reference to Mexica, also known as "Aztecs" although they referred to themselves as Mexica. It subsequently became a cabecera of the Viceroyalty of New Spain.