From around 500 BC, maize farming communities in the north-west were developing into regional chiefdoms, distinguished by diverse pottery styles. Often they fought with each other, but they also traded peacefully.
Extensive trading contacts linked not only coastal and highand chiefdoms but also these chiefdoms with Central America to the north and the Andean states to the south.
Each chiefdom was different, but they had many similarities. Particularly distinctive is their fine goldwork. Many began constructing major earthworks, particularly in ceremonial centres.
These often followed the widespread style of mounds, sometimes in the form of pyramids, and sometimes faced with stones, surrounding a central plaza with associated stone statues of divine beings.
Those of San Agustin, La Tolita and BahÌa are particularly notable. Some regional groups also built massive tombs, like the burial mounds at San Agustin containing stone shaft tombs in which were placed carved stone sarcophagi.
Other major public works included roads and canals, as in the contemporary states of the Andes. After AD 500, these chiefdoms became larger and less numerous.
