Commercium, conubium, migratio. Immigrazione e diritti nell'antica Roma

After providing brief notes on social mobility, frequent already in archaic Rome, the paper addresses some problems regarding immigration in the Urbe from its start to the end of the Republic. Special attention is reserved to the criteria of registration in the tribes and to the legal regulation of the conubium and the migratio Romam, prohibited in the last century BCE, unlike the always allowed commercium. Some opinions on the problem of citizenship and connected legal measures are reviewed. Finally, the paper outlines the universal extension of Roman citizenship with the constitutio Antoniniana which starts the late antiquity epilogue on the matter of the legal gap between Roman and foreign citizens.