Like many archaeological sites, Conímbriga was evolved sequentially and built up by successive layers, with the primary period of occupation beginning in the 9th century BCE; during this period the area was occupied by the Castro culture. Before the Roman occupation, the indigenous Conii peoples (who would later settle in southern Portugal) lived here. The Conímbriga designation came from , used by indigenous peoples to designate "the place of rocky eminence," and , the Celtic suffix meaning "citadel". This site had become a junction between the road that linked Olisipo to Bracara Augusta, by way of Aeminium (Coimbra).