The earliest human remains in Mexico are chips of stone tools found near campfire remains in the Valley of Mexico and radiocarbon-dated to c. 23,000 years ago. Mexico is the site of the domestication of maize and beans which caused a transition from paleo-Indian hunter-gatherers to sedentary agricultural villages beginning around 7000 BCE.
In the subsequent formative areas maize cultivation and cultural traits such as a complex mythological and religious complex, a vigesimal numeric system, were diffused from the Mexican cultures to the rest of the Mesoamerican culture area. In this period villages began to become socially stratified and develop into chiefdoms, and the development of large ceremonial centers.
Among the earliest complex civilizations in Mexico was the Olmec culture which flourish on the gulf coast from around 1500 BCE. Olmec cultural traits diffused through Mexico into other formative era cultures in Chiapas, Oaxaca and the Valley of Mexico. The formative period saw the spread of distinct religious and symbolic traditions, as well as artistic and architectural complexes. In the subsequent pre-classical period, complex centers began to develop among the Maya with centers at Calakmul and the Zapotec at Monte Albán. During this period the first true Mesoamerican writing systems were developed in the Epi-Olmec and the Zapotec cultures, and the Mesoamerican writing tradition reached its height in the Classic Maya Hieroglyphic script.
In Central Mexico, the height of the classic period saw the ascendancy of Teotihuacan which formed a military and commercial empire whose political influence stretched south into the Maya area and north. At its peak, Teotihuacan, containing some of the largest pyramidal structures built in the pre-Columbian Americas, had a population of more than 150,000 people. At the collapse of Teotihuacán around 600 CE,