The Olmecs were an early civilization that shaped the religion, trade practices, and technology of later civilizations in Mesoamerica. They flourished in the coastal lowlands of Mexico along a region stretching from Veracruz to the Yucatán from 1500 to 300 B.C.E. The Olmecs formed the first cities of Mesoamerica, and these cities served as centers of agriculture, trade, and religion (Map 11.1). Through long-distance trade, the Olmecs spread their culture and technology across Mesoamerica, establishing beliefs and practices that became common to the civilizations that followed.

The Olmecs settled and farmed along rivers in coastal lowlands, where they cultivated maize, squash, beans, and other plants and supplemented their diet with wild game and fish. But they lacked many other resources. In particular, they carried stone for many miles for the construction of temples and for carving massive monuments, many in the shape of heads. Across far-flung networks the Olmecs traded rubber, cacao (from which chocolate is made), pottery, clay figures, and jaguar pelts, as well as the services of artisans such as painters and sculptors, in exchange for obsidian, a volcanic glass that could be carved to a razor-sharp edge and used for making knives, tools, spear tips, and other weapons.

These ties between the Olmecs and other communities spread religious practices, creating a shared framework of beliefs among later civilizations. These practices included the construction of large pyramid temples, as well as acts that ranged from blood sacrifice, in which nobles ritually cut and bled themselves but did not die, to human sacrifice, in which the subject died. In addition to the manner of worship, archaeologists can trace the nature of the deities common in Mesoamerica. Olmec deities, like those of their successors, were combinations of gods and humans, included merged animal and human forms, and had both male and female identities. People practicing later religions based their gods on the fusion of human and spirit traits along the lines of the Olmec were-jaguar: a half-man, half-jaguar figure.

The Olmecs also used a Long Count solar calendar — a calendar based on a 365-day year. This calendar begins with the year 3114 B.C.E., though its origins and the significance of this date are unclear. Archaeologists presume that the existence of the Long Count calendar meant that the Calendar Round combining the 260-day and 365-day years already existed as well. All the later Mesoamerican civilizations used at least one of these calendars, and most used both of them.