Roman Law to Isidore of Seville
In Ancient Rome, the oldest traces of â€?public international law' are found withÂin iusfetiale rather than within ius gentium.[486] In fact, ius fetiale regulated the rites used by the fetial priests to declare war or conclude a treaty with a foreign people; ius gentium, on the other hand, might originally have been a sort of interregional private law, mainly related to commercial practice, and stemÂming from the jurisdiction of the praetor peregrinus, i.e.
the Roman magistrate created at the end of the First Punic War (242 bce) to hear cases in which nonÂcitizens were parties.[487] The remedies introduced by the praetor peregrinus came to be seen as applying to all nations and were made available to citizens and non-citizens alike, as opposed to ius civile, which applied exclusively to Roman citizens.[488] The most important innovation brought by these remedies to the legal system was the recognition of the validity of consensual agreements, which did not need any formality and were based on good faith (bona fides): they included sale, hire, mandate and partnership.It is difficult to connect this praetorian law with subsequent jurisprudential elaboration on the concept of ius gentium.[489] The idea of a universal recognition of the remedies introduced by the praetor peregrinus might have suggested that they should be based not on common practice, but on natural reason, â€?which all men shared as part of their human nature’.[490] In fact, although at the time it may already have been an accepted technical concept, the term ius genÂtium is first to be found in the work of Cicero (106 BCE-43 BCE), where it is associated with natural law. The distinction, within the field of political justice, between natural justice and legal justice was an ancient one, and can be traced back to Aristotle.[491] Stoic philosophers then elaborated a cosmopolitan notion of humanity and a notion of natural law innate in human nature.
Possibly unÂder this influence, Cicero distinguished ius gentium from ius civile, considering the latter to be subordinated to the former, which he also identified with natuÂra.[492] Nonetheless, in his writings another meaning of ius gentium can also be found, which is closer to the idea of a positive law common to all nations and grounded on custom, than to the Stoic notion of a law common to all men and grounded on reason.[493] [494] In fact, as we shall see, this ambiguity was to characterÂize the concept of ius gentium for a long time.The philosophical notion of ius gentium was later developed by Gaius (d. c. 180) who, at the beginning of his Institutiones, provided a definition of ius genÂtium and ius civile: whereas the latter is the positive law enacted by each people for itself, the former is â€?the law which natural reason has established among all human beings’ and is therefore observed in equal measure by all peoples; and it is called ius gentium â€?as being the law which all gentes observe'.n In a passage of the Res cottidianae later collected in Dig. 41.1.1, ius gentium and ius civile are again distinguished: having been established among all mankind by natural reason, the former is more ancient than the latter, â€?as it was promulgated at the time of the origin of the human race’.[495] [496] [497] [498] [499] In so doing, Gaius emphasized the logiÂcal and chronological priority of ius gentium over ius civile, and the rational character of human nature. The question of whether this notion of ius gentium was more influenced by the Stoic idea of the logos as the basic principle of cosmic order, or by the Aristotelian two-part taxonomy of law (one law comÂmon to all mankind, another belonging to each people, both being intended as a purely human phenomenon), is still debated?3 It has also been suggested that the idea of â€?natural reason’ might have been rooted in a common set of ancient values proper to the societies of the Mediterranean?4 In the passages above, Gaius does not define ius naturale; more broadly, in his texts a fundamental uncertainty remains as to the difference between ius naturale or naturalis ratio and ius gentium.15 A distinction between these two concepts was subsequently drawn by Ulpian (c. In contrast to the formal definitions formulated by Gaius and Ulpian, Her- mogenian (around the turn of the third century into the fourth century) proÂvided in his Epitome Iuris a material definition of ius gentium, consisting of a simple list of the institutions it encompasses. This definition was inserted in the Digesta immediately after Ulpian’s passage on manumissiones: â€?As a conseÂquence of this ius gentium, wars were introduced, nations differentiated, kingÂdoms founded, properties individuated, estate boundaries settled, buildings put up, and commerce established, including contracts of buying and selling and letting and hiring (except for certain contractual elements established through ius civile)’.[503] Nothing is said here about the foundations of ius gentium: as has been remarked, the wording of the text indicates that the institutions it enumerates do not constitute ius gentium, but were introduced after it, and on its basis.[504] [505] [506] [507] [508] [509] Unlike Gaius and Ulpian, Hermogenian evokes the idea of an hisÂtorical development, to the extent that ius gentium here appears to have been cut off from ius naturale and given an historical and consensual nature. It is noteworthy, moreover, that the text lists not only private law institutions, but also three institutions relating to public international law.22 This is all the more remarkable in view of the fact that, first, all the discussion about ius naturale, ius gentium and ius civile in the Digesta is presented after the partition between ius publicum and ius privatum has been introduced (Dig. 1.1.1.2), and the three legal systems are all put into the second category; and, secondly, as shown by Max Kaser, most references to ius gentium in the classical Roman legal texts deal with private law institutions?3 That said, this connection between ius gentium and public international law institutions in Hermogenian’s text was not something new. Some second- century legal sources had already understood ius gentium as related to foreign relations, although jurists were only then beginning to use the concept. The best example is probably the passage of Sextus Pomponius collected in Dig. 50.7.18, which reports opinions attributed to Publius (d. 115 bce) and Quintus Mucius Scaevola (d. 82 bce): â€?If someone strikes an ambassador of the eneÂmy, he is regarded as having acted against ius gentium, because ambassadors are regarded as inviolable’?4 Before Pomponius, the same use of the term ius gentium had been made by historians and philosophers like Sallust, Seneca, Tacit and, above all, Livy?5 who employed the term some forty times with reÂgard to diplomatic relations between Rome and other peoples, mentioning for example the prohibition of the mistreatment of ambassadors?6 the loss of immunities for ambassadors who misbehave during their mission,[510] and the lawfulness of armed defence against an armed attack not preceded by a forÂmal declaration of war?[511] [512] Given all of the above, in his reference to institutions related to public international law, Hermogenian seems to be confirming an already established use of the term ius gentium. Upon the convergence of these formulations of Gaius and Ulpian, another - possibly from the Institutiones of Aelius Marcianus (from the second or third century) - was added to the mix in a rather confusing passage of Justinian’s Institutiones that deals with the tripartition of ius naturale, ius gentium and ius civile.29 Justinian’s commission here retained only the first part of Ulpian’s defiÂnition, concerning ius naturale; after a brief transitional passage, it then quotÂed Gaius’ definition of ius civile and ius gentium, and omitted the second part of Ulpian’s text. ius gentium is common to the entire human race, for gentes have estabÂlished for themselves certain regulations exacted by custom and human necessity. For wars have arisen, and captivity and slavery, which are conÂtrary to natural law, have followed as a result, as, according to ius natuÂrale, all men were originally born free; and from ius gentium nearly all contracts, such as purchase, sale, hire, partnership, deposit, loan, and inÂnumerable others have been derived.[514] [515] [516] Marcianus' definition makes it clear that the source of ius gentium is not naÂture, but human will impelled by practical needs. This move towards positive law is emphasized by the explicit remark that ius gentium (insofar as it encomÂpasses war, captivity and slavery) distances itself from the precepts of ius natu- rale.32 Incidentally, and contrary to what has just been said in the passage takÂen from Ulpian, ius naturale as understood by Marcianus is rooted in â€?divine providence' rather than in nature, and is common only to mankind: â€?natural laws [naturalia iura] that are observed without distinction by all gentes and have been established by a certain divine providence remain always fixed and unchangeable; but those which every civitas establishes for itself are often changed either by the tacit consent of the people, or by some other law subseÂquently enacted'.33 Returning to ius gentium, Marcianus' definition indicates a set of institutions and, several decades before Hermogenian's, divides these institutions even more explicitly into two groups, those relating to a category akin to public international law, and those relating to private law. The semantic stratification of Roman law ideas from this time defies any attempt to find a synthesis between the various definitions laid out in the legal texts. Ius civile is plainly described as a positive law established by each people and subject to change over time; ius naturale, whether grounded in nature or in divine providence, common to all animals or only to mankind, encompasses a set of fundamental norms that are not alterable by human will; but it is hard to say where exactly ius gentium is situated between the two. In Gaius, it almost blends with ius naturale (which, however, he does not define), sharing with it both origin and scope. In Marcianus and Hermogenian, ius gentium appears much closer to ius civile than to ius naturale with regard to origin, although its scope is wider. Ulpian's definition, lastly, is simply too vague to allow any asÂsumption to be made as to what he considers to be the natural or historicalÂpositive origin of ius gentium. Without doubt, at least part of the trouble faced by later interpreters stemmed from the extrapolation of these definitions from their original contexts and juxtaposition in the legal compilations promulgatÂed by Justinian.[517] [518] In sum, Roman jurists were concerned with ius gentium more in terms of general jurisprudence, or of private law, than in terms of public international law. This is particularly evident in the definitions provided by Ulpian and GaiÂus: the former put ius gentium into the category of â€?private law' as opposed to â€?public law,,3≡ whereas both of them maintained that ius gentium applied to men rather than to polities [519] As a result, the prime subjects of ius gentium were individuals. Historically, as we have seen, ius gentium concerned relations between Roman citizens and people without the status civitatis. After 212, howÂever, when the constitutio antoniniana granted full civil status to all free inhabÂitants of the Empire, even the distinction between ius civile and ius gentium began to lose its significance, and ius gentium thus increasingly became underÂstood as a sort of universal law[520] [521] Nevertheless, although â€?public international law' or anything of its kind was not studied as a specific domain, Livy, Seneca, Tacitus and Pomponius all worked to establish a connection between ius genÂtium and the institutions related to it. Pivotally, this connection was later deÂveloped by Marcianus and Hermogenian, who, in mentioning these instituÂtions first in their definitions, seem to have given them primacy. A later text, too, bears witness to this growing interest in interpolity relaÂtions: the Etymologiae compiled by Isidore of Seville (c. 560-636), which, more than any other, contributed to the transmission of classical learning to the Christian Middle Ages. Isidore comes to ius gentium after talking about ius naturale and ius civile, and before moving on to ius militare, ius publicum and ius Quiritum. His definition of ius naturale is modeled on Ulpian's, insofar as it refers to natural instinct and to institutions like the union of the sexes, and the children's inheritance and education, but he limits its scope to human na- tions.38 On the other hand, ius civile is â€?that which each people or civitas has established particular to itself, for divine or human reason’.[522] As for ius genÂtium, Isidore's definition, which consists of a list of institutions, is fairly close to that of Hermogenian, although the (short) etymological explanation with which he concludes seems to evoke Gaius’ Institutiones: Ius gentium concerns the occupation, building, and fortification of settleÂment regions, wars, captivities, enslavements, the right of return, treaties of peace, truces, the inviolability of ambassadors, the prohibition of marÂriages between different races. And it is called ius gentium because nearly [fere] all nations use it.[523] Alvaro d’Ors and Juan de Churruca have argued that, by introducing the word fere, Isidore was omitting the barbarians (which Gaius had not mentioned, limiting his scope to the Mediterranean people in regular contact with Rome). Laurens Winkel has explained this difference by recalling the Stoic influence on Gaius’ definition, in which â€?the ratio was supposed to be shared with every human being, independently from legal relations with Rome’?[524] Whatever it be, it is important to point out that Isidore relates ius gentium almost exclusively to the field of relations between and among polities[525] Like Marcianus and Hermogenian, he seems to understand iusgentium as positive law, grounded in custom; yet, unlike them, he excludes property and contracts, and focuses on the institutions that concern relations between polities, adding to their list peace agreements, truces and the inviolability of ambassadors. Our limited knowledge of the sources used for this section of the Etymologies makes it difÂficult to say how original this passage was; but Isidore’s emphasis on foreign relations has been linked to Patristic thought on this domain, and especially to Augustine’s teaching on just war.[526] [527] 2