Between 5000 and 1000 BCE, hunter-gatherer tribes transitioned to agrarian societies; fixed settlements were established, and pottery appeared. Beginning in the 1st millennium BCE, groups of Amerindians including the Muisca, Zenú, Quimbaya, and Tairona developed the political system of ''cacicazgos'' with a pyramidal structure of power headed by ''caciques''. The Muisca inhabited mainly the area of what is now the Departments of Boyacá and Cundinamarca high plateau (''Altiplano Cundiboyacense'') where they formed the Muisca Confederation. They farmed maize, potato, quinoa, and cotton, and traded gold, emeralds, blankets, ceramic handicrafts, coca and especially rock salt with neighboring nations. The Tairona inhabited northern Colombia in the isolated mountain range of Sierra Nevada de Santa Marta. The Quimbaya inhabited regions of the Cauca River Valley between the Western and Central Ranges of the Colombian Andes. Most of the Amerindians practiced agriculture and the social structure of each indigenous community was different. Some groups of indigenous people such as the Caribs lived in a state of permanent war, but others had less bellicose attitudes.