The north-east of the Central African Republic and the east of Cameroon were the only geographical zones in central Africa to have important concentrations of megalithic monuments. The objective of the eleven years of research work reported on here was to understand the role and place of the megalithic phenomenon, and notably the relation of megaliths with systems of symbolic representation, in the societies of the Central African Republic from 2500 BC. A firm chronological framework is presented, together with a fresh analysis of material culture, derived from a systematic programme of fieldwork comprising survey, sondages and excavation. Three cultural periods are distinguished and iron-working activity is shown to be present from the 9th century BC. The interactions of the whole cultural order are explored: at the level of pottery manufacture, iron-working and megalith construction.