The Aztecs settled there because of the security afforded by its islands and shallow waters - their city, Tenochtitlan, being so completely surrounded by water that a handful of warriors could easily defend its approaches against a greatly superior force.
The Aztec name of the city was Tenochtitlan, derived either from Tenoch, one of their priests and leaders, or from tenuch, the Indian name for the " nopal," which is associated with its foundation.
About 1325 they founded on the lake of Tezcuco the permanent settlement of Mexico Tenochtitlan, which is still represented by the capital city, Mexico.
As one of the Aztec chiefs at the time of the founding of their city was called Tenoch, it is likely that from him was derived the name Tenochtitlan or " Stone-cactus place."
Mexico-Tenochtitlan, founded about 1325, for many years afterwards probably remained a cluster of huts, and the higher civilization of the country was still to be found, especially among the Acolhuas in Tezcuco.
The wars of this nation with the Tepanecs, which went on into the 15th century, were merely destructive, but larger effects arose from the expeditions under the Culhua king Acamapichtli, where the Aztec warriors were prominent, and which extended far outside the valley of Anahuac. Especially a foray southward to Quauhnahuac, now Cuernavaca, on the watershed between the Atlantic and Pacific, brought goldsmiths and other craftsmen to Tenochtitlan, which now began to rise in arts, the Aztecs laying aside their rude garments of aloe-fibre for more costly clothing, and going out as traders for foreign merchandise.
When the first Moteuczoma was crowned king of the Aztecs, the Mexican sway extended far beyond the valley plateau of its origin, and the gods of conquered nations around had their shrines set up in Tenochtitlan in manifest inferiority to the temple of Huitzilopochtli, the war-god of the Aztec conquerors.