The development of the hillfort in prehistoric Ireland WILLIAM O’BRIEN * [Accepted 28 July 2017. Published 22 September 2017] Hillforts are one of the best known, and certainly the largest, monuments of the later prehistoric period in Ireland. Their immense size testiies to the signif- icance these central places held in economic, political and ideological terms for societies of the later Bronze Age. Hillforts were centres for high-status residence, ceremony and assembly, and a visual expression of power in the landscape. Their occurrence is another manifestation of a warrior culture that spread across Eu- rope during the later second millennium BC. This paper presents the results of a recent investigation of hillfort chronology in Ireland. The irst examples were built c.1400–1200 BC during the Middle Bronze Age, and the number of hillforts grew signiicantly during the twelfth and eleventh centuries BC into the Late Bronze Age. The possibility of hillforts dating to other periods of Irish prehis- tory is also considered in relation to hilltop enclosures of the Early Neolithic and Iron Age. The hillfort played an important role in the emergence of complex societies in late prehistoric Europe. The imposing size and landscape setting of these great enclosures relect the signiicance they held, from their military associations to their use as central places of assembly and elite residence with important eco- nomic, social and ceremonial functions. The building of hillforts was connected to a new type of political structure and centralized leadership in social forma- tions often classiied as ‘chiefdoms’. Within these societies, hillforts represented a conspicuous display of power in the landscape. This paper presents the results of recent archaeological ieldwork in southern Ireland, which examined different manifestations of the hillfort phenomenon during the Neolithic and Bronze Age. The signiicance of hillforts The purpose of hillforts is much debated across Europe, with opinion divided between researchers who regard them as defensive strongholds, and those who argue for wider meaning in economic, social and ideological terms. The physical barriers presented by these sites represent control of a culturally signiicant place * Author’s email: w.obrien@ucc.ie doi: https://doi.org/10.3318/PRIAC.2017.117.08 Proceedings of the Royal Irish Academy Vol. 117C, 1–59 © 2017 Royal Irish Academy Abstract Introduction