According to The Columbia Encyclopedia, the Aztec capital Tenochtitlán was founded circa 1325 A.D. It was at this point that the organized Aztec civilization began, as they had previously been a poor tribe of nomads. The Aztecs reached the height of their power during the 15th and 16th centuries.
The Aztecs dominated central Mexico before the time of the Spanish conquest. Their civilization was founded on absorbing external cultural elements and on conquest enabled by an efficient, sizable army. The Aztecs developed advanced skills in architecture, art, astronomy, engineering and mathematics. Well-developed agriculture was a further notable aspect of the civilization.