Group of six Tiwanaku period ceramic keros (drinking vessels). a.d 400 - a.d. 1000. Vessels such as these are rare. They were used in ritual drinking bouts that were part of the most important ceremonies conducted at the sacred site of Tiwanaku and other related ritual centers in the Lake Titicaca Basin. These ceramic vessels were used for consuming a beer-like beverage usually made from fermented corn or other grains known as chicha. Ritual drinking was an essential element in Andean ceremonial life. Elaborate feasting and drinking events helped to cement binding social relationships and cooperation between participating kinship, clan and disparate regional populations who gathered during various seasonal celebrations to perform important rituals and to work on large scale communal agricultural projects as well as construction of monumental buildings like those at the site of Tiwanaku. Additional images, condition reports and information available upon request.