The wooden coffin burial system, locally known as erong, is a unique culture in Toraja, and very little is known about it, especially regarding the various types of coffin and when this culture began. In 2010, a systematic survey was conducted in several burial sites and samples were collected for radiocarbon dating. The research also included an ethno-archaeological study. An investigation was undertaken at 19 sites and 100 of wooden coffins were discovered. These coffins fell into three categories; boat-shaped types, buffalo-shaped types, and pig-shaped types. These coffins were always placed in cliffs, caves, or niches and were located close to a village or rice field and garden. The type and placement of wooden coffins in Tana Toraja was strongly influenced by the deeply-rooted beliefs and social system in the Aluk Todolo doctrine. Wooden coffins were only used for nobles, and the type of coffin used was based on what role the noble had played within the society or community. Radiocarbon dating results suggest that wooden coffins have been used in Toraja from at least c. 800 BC and were still being used up until the 1960s.