Chiefdom‐based civilization, the earliest in Mesoamerica, comprised of numerous small polities that flourished around the Gulf of Mexico in central Mexico from about 1200 to 600 bc. The origins of Olmec Culture are not clear, some scholars preferring a local development involving the transformation of tribal farmers, while others advocate a migration from Guerrero or Oaxaca. High agricultural production was a key to their success, and Olmec communities mainly settled beside slow‐flowing rivers which during times of flood produce fertile alluvial soils.
San Lorenzo, occupied 1200–900 bc, seems to have been the main Olmec settlement, supported by two other centres, Tenochtitlán (not the same as the Aztec capital of the same name) and Potrero Nuevo. All the Olmec ceremonial centres comprised complexes of platforms supporting ceremonial courts, house mounds, stone monuments (including carved stone heads, altars, and large free‐standing sculptures), and large conical pyramids. The large stone heads are particularly distinctive, up to 3 m tall, and thought to be representations of chiefs and the elite of Olmec society. The labour to build these sites was found from among the agricultural population living in widely scattered hamlets in the lowland areas of the country.
Trade was important and again focused on the ceremonial sites: obsidian, magnetite, serpentine, and mica were among the materials acquired through exchange. More local exchange networks must also have existed, and together with the long‐distance network served to spread the Olmec way of life and the sophisticated cosmology that went with it over wide areas. Olmec priests had developed a 260‐day calendar and a set of beliefs which involved a were‐jaguar (a mythical being that changes from a jaguar to a human being) and a flaming serpent. The Olmec style of art is visible mostly in sculpture and is realistic in its representation of natural and supernatural forms. Craftsmanship of a very high order is represented in objects of shell and jadeite.
By soon after 600 bc Olmec culture was waning and the exchange systems had decreased in their intensity. The settlement pattern expanded and previously sparsely settled areas were infilled, especially in the Valley of Mexico. The development of the Olmec did, however, set the stage for the appearance of other advanced civilizations in the area in succeeding centuries.