Citizens and Aliens
A very important division of persons in Roman law was the division into citizens and aliens (peregrini). A citizen was one who had full legal capacity and enjoyed full legal rights in all matters of public and private law, that is, the Jus Civile.
But from early times outsiders were drawn to Rome by trade or for other reasons, and also with the extension of Roman dominion, the Roman territory was enlarged so as" to embrace many persons not Roman citizens, so that in time there were in the Roman state a large number of persons who were known as peregrini or aliens.
A peregrimis at first enjoyed no rights under the Jus Civile. He could not appear in his own right in a court of law, but only as represented by a Roman citizen under whose protection he placed himself, somewhat in the relation of patron and client.
But while the Jus Civile did not apply to the peregrini. they were not without law. In time there grew up for them a distinct body of law known as the Jus Gentium, which ultimately developed,' along with the Jus Civile, into the law of Rome. By degrees the rights of citizens were extended to aliens, and when, during the Empire, citizenship was made universal, the distinction between citizens and aliens became obsolete.