Title translation: ‘Segmentary Societies or Feudal States? Early Medieval Ireland and the Interpretation of the Archaeological Record' Using early medieval Ireland as a case study, the chapter examines to what degree social complexity can be identified in the archaeological record. The early medieval period in Ireland is well attested in both historical and archaeological sources. Historical and archaeological sources are analysed separately, to demonstrate the different degrees of social complexity that can be observed in them. The first part of the analysis assesses whether ethnic groups – a currently popular classificatory tool for prehistoric societies in archaeology – can be identified in the Irish archaeological record. It is examined whether it is possible to relate the archaeological evidence to the multi-layered concepts of ethnic and quasi-ethnic identity as can be found in the medieval historical sources. The second part of the analysis assesses whether the high degree of social complexity, demonstrated in the historical sources by well-defined status and professional social classes, is also observable in the archaeological record. It is demonstrated that in both areas examined, the social complexity observable in the archaeological record is far lower than that observable in the historical record. While the archaeology of early medieval Ireland seems to show quite simple, segmentary societies, the historical sources present us with highly complex stratified societies. It is concluded that archaeological methods to analyse social complexity can only demonstrate a terminus super quem, the lowest possible degree of social complexity in the assessed societies.