In the early law, and to a considerable extent throughout Roman history, the family is the legal unit. Its head, the paterfamilias, is the only full person known to the law. His children, of whatever age, though they are citizens and therefore have rights in public law, are subject to his unfettered power of life and death. Again, only he can own property, and anything which his children acquire belongs to him alone. This patria potestas was thought by the Romans to be peculiar to themselves. The powers of a Greek father served only a protective purpose, like those of a guardian, and ended when the child came of age.
It is the existence of slaves like these that differentiates Roman slavery from any that the modern world has known, and which explains the bulk and complexity of the Roman law governing the consequences of their transactions. The laborer on the plantation provides little scope for the private law. The Roman jurist did not suppose that the detailed rules of the Greek contract of sale were the same as those of emptio venditio. Ius gentium had a second sense, however, which was of considerable practical importance.
In this sense it was that part of Roman law which was applied both to citizens and to peregrines. Ancient law was in principle ‘personal’: the law by which a man lived depended not on where he was, but on who he was—on his nationality. Roman law applied to Roman citizens, Athenian law to Athenian citizens. Such a principle presents obvious problems. What in fact emerged was something quite different—a body of law, Roman in character but without the formality and technicality of the old ius civile, which could be applied to citizen and non-citizen alike.
How this law grew up remains a matter of conjecture. Its main features were already fixed in the last century B. C. , and our knowledge of the period before then is very slight. The Peregrine Praetor, whose province it was to administer just such a law, must have played a large part, as also perhaps did the provincial governors, who were faced with the same problem, but we lack the evidence to go farther than this. Moreover, as we know it, this body of law applied not only to transactions involving peregrines, but even to transactions wholly between citizens.
If therefore it originated in the Edict of the Peregrine Praetor, it had in some way been ‘received’ into the province of the Urban Praetor. And there must have been some ‘reception’ in the reverse direction also. All that is certain is that in Gaius the term is used both in the philosophical or theoretical sense discussed above and in this practical sense, and that in either sense it embraces the greater part of the law outside the law of persons and the law of succession.
Without it the Roman law would never have held the place in history that it does, and yet we know next to nothing of its origin or growth. The two senses of ius gentium are often indistinguishable. Most of the ius gentium in the practical sense is informal and simple and therefore ‘universal’. But while all institutions of the ius gentium in the theoretical sense were necessarily part of the ius gentium in the practical sense, the converse was not always so. The stipulatio, already mentioned, makes this plain.
It existed in no system except the Roman, but it was open to citizens and peregrines alike. The distinction emerges also in the use of the term ius civile. Like our term ‘common law’, ius civile derives its meaning from its context. By contrast with ius gentium in the theoretical sense it denotes the law peculiar to a particular state; by contrast with ius gentium in the practical sense it denotes that part of Roman law which is confined to Roman citizens. In the first sense stipulatio is of the ius civile, in the second it is not.
There is, moreover, a third sense of ius civile which must be borne in mind. By contrast with ius honorarium it denotes—and it is principally in this sense that we shall use it —that part of Roman law which derives from lex and interpretatio.
Borkowski, A. Textbook on Roman Law, (2nd ed. , 1997). Buckland, W. W. Textbook of Roman Law (3rd ed. , P. Stein, 1963) Jolowicz H. F. and B. Nicholas, Historical Introduction to the Study of Roman Law (3rd ed. , 1972)