Mexico-Tenochtitlan  audio (help·info), 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 Aztec 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. Today the ruins of Tenochtitlan are located in the central part of Mexico City.Traditionally, its name was thought to come from Nahuatl tetl /ˈtetɬ/ ("rock") and nōchtli /ˈnoːtʃtɬi/ ("prickly pear") and is often thought to mean "Among the prickly pears [growing among] rocks". However, one attestation in the late 16th-century manuscript known as "the Bancroft dialogues" suggest the second vowel was short, so that the true etymology remains uncertain. Tenochtitlan was one of two Mexican altepetl (city-states) on the island, the other being Tlatelolco.