In the pre-classical period (2000 BC - 250 AD), the Olmecs and Zapotecs stand out. The Zapotec culture (600 BC - 1521) developed in the Oaxaca Valley in the south of the Mexican Highlands. Zapotecs built cities; they had a writing system and a calendar. The basis of the economy was agriculture based on irrigation. The capital of the Zapotecs Monte Alban was the largest city in southern Mexico.
The later Olmec cities were temple centers. The Olmec culture is one of the earliest cultures of Mesoamerica. Almost nothing is known about the social structure and political structure of the "Olmec" society. An analysis of the burial complexes shows that the process of property differentiation in the local society has gone quite far. The presence of ritual centers with a certain layout indicates a fairly high level of organization of power. The role of the leader, carrying out primarily military functions, is taking place.
