Every production model requires a constant supply of labor. There is a tension between the need to attract labor to certain nuclei of economic activity and the difficulty of retaining it in others. This dialectic tension has been expressed in a number of systems to legally regulate migration, which can be repressive or permissive in nature. This paper is a historical review of the rules on migration present in Antiquity, specifically during the Roman Empire, a period in which an Agrarian Capitalism was developed and, consequently, a legal model of open mobility was implemented. This model remained in force until the decline of slavery in late Antiquity, which brought the subjection of labor to geographical areas and specific economic activities, where the old citizens, ever less free, took the place of slaves. The aim of this paper is to give light to the sense of the present immigration regulations, through the historical review of legal systems of the past.