By the early 1500s, the Mexica, or Aztecs, the last of the great pre-Columbian Mesoamerican civilizations, dominated an empire of some six million people. In 1325 they had begun to build their capital, Tenochtitlan, on land that is today Mexico City. Their culture, and especially their mythology, developed from that of the Toltec. As did the Toltec, they spoke Nahuatl; and, like the Toltec, they were militaristic and commercial. The Toltec and Aztec shared a tradition based on sacrifice, solar dominance, and many of the same deities. Many of these traditions were inherited indirectly from the Olmec and Monte Alban peoples. Aztec civilization was still developing when the Spanish, led by Cortés, conquered it in 1521.