摘要:Starting from the suggestions coming from recent historical studies on the concept of border, we mean to analyse the border area between the regnum Langobardorum and the Byzantine Exarchate in Italy. The subject of the research is the group of castra in the Emilia region along the territories of the regnum mentioned in the sources in the 8th century, and mainly the castrum Persiceta . The analysis shows how the frontier were an uncertain bordering ambit, an area of political separation, and tries offering an interpretation that, through the analysis of long term processes, points out the specificity of castra as framework units for the population and media between local powers and central political structures in the period from the 5th to the 9th century.