Chapter 3. Law of Nature and Equity

　　The theory of a set of legal principles， entitled by their intrinsic superiority to supersede the older law， very early obtained currency both in the Roman state and in England. Such a body of principles， existing in any system， has in the foregoing chapters been denominated Equity， a term which， as will presently be seen， was one （though only one） of the designations by which this agent of legal change was known to the Roman jurisconsults. The jurisprudence of the Court of Chancery， which bears the name of Equity in England， could only be adequately discussed in a separate treatise. It is extremely complex in its texture and derives its materials from several heterogeneous sources. The early ecclesiastical chancellors contributed to it， from the Canon Law， many of the principles which lie deepest in its structure. The Roman law， more fertile than the Canon Law in rules applicable to secular disputes， was not seldom resorted to by a later generation of Chancery judges， amid whose recorded dicta we often find entire texts from the Corpus Juris Civilis imbedded， with their terms unaltered， though their origin is never acknowledged. Still more recently， and particularly at the middle and during the latter half of the eighteenth century， the mixed systems of jurisprudence and morals constructed by the publicists of the Low Countries appear to have been much studied by English lawyers， and from the chancellorship of Lord Talbot to the commencement of Lord Eldon''s chancellorship these works had considerable effect on the rulings of the Court of Chancery. The system， which obtained its ingredients from these various quarters， was greatly controlled in its growth by the necessity imposed on it of conforming itself to the analogies of the common law， but it has always answered the description of a body of comparatively novel legal principles claiming to override the older jurisprudence of the country on the strength of an intrinsic ethical superiority.

　　The Equity of Rome was a much simpler structure， and its development from its first appearance can be much more easily traced. Both its character and its history deserve attentive examination. It is the root of several conceptions which have exercised profound influence on human thought， and through human thought have seriously affected the destinies of mankind.

　　The Romans described their legal system as consisting of two ingredients. “All nations，” says the Institutional Treatise published under the authority of the Emperor Justinian， “who are ruled by laws and customs， are governed partly by their own particular laws， and partly by those laws which are common to all mankind. The law which a people enacts is called the Civil Law of that people， but that which natural reason appoints for all mankind is called the Law of Nations， because all nations use it.” The part of the law “which natural reason appoints for all mankind” was the element which the Edict of the Praetor was supposed to have worked into Roman jurisprudence. Elsewhere it is styled more simply Jus Naturale， or the Law of Nature； and its ordinances are said to be dictated by Natural Equity （naturalis aequitas） as well as by natural reason. I shall attempt to discover the origin of these famous phrases， Law of Nations， Law of Nature， Equity， and to determine how the conceptions which they indicate are related to one another.

　　The most superficial student of Roman history must be struck by the extraordinary degree in which the fortunes of the republic were affected by the presence of foreigners， under different names， on her soil. The causes of this immigration are discernible enough at a later period， for we can readily understand why men of all races should flock to the mistress of the world； but the same phenomenon of a large population of foreigners and denizens meets us in the very earliest records of the Roman State. No doubt， the instability of society in ancient Italy， composed as it was in great measure of robber tribes， gave men considerable inducement to locate themselves in the territory of any community strong enough to protect itself and them from external attack， even though protection should be purchased at the cost of heavy taxation， political disfranchisement， and much social humiliation. It is probable， however， that this explanation is imperfect， and that it could only be completed by taking into account those active commercial relations which， though they are little reflected in the military traditions of the republic， Rome appears certainly to have had with Carthage and with the interior of Italy in pre-historic times. Whatever were the circumstances to which it was attributable， the foreign element in the commonwealth determined the whole course of its history， which， at all its stages， is little more than a narrative of conflicts between a stubborn nationality and an alien population. Nothing like this has been seen in modern times； on the one hand， because modern European communities have seldom or never received any accession of foreign immigrants which was large enough to make itself felt by the bulk of the native citizens， and on the other， because modern states， being held together by allegiance to a king or political superior， absorb considerable bodies of immigrant settlers with a quickness unknown to the ancient world， where the original citizens of a commonwealth always believed themselves to be united by kinship in blood， and resented a claim to equality of privilege as a usurpation of their birthright. In the early Roman republic the principle of the absolute exclusion of foreigners pervaded the Civil Law no less than the Constitution. The alien or denizen could have no share in any institution supposed to be coeval with the State. He could not have the benefit of Quiritarian law. He could not be a party to the nexum which was at once the conveyance and the contract of the primitive Romans. He could not sue by the Sacramental Action， a mode of litigation of which the origin mounts up to the very infancy of civilisation. Still， neither the interest nor the security of Rome permitted him to be quite outlawed. All ancient communities ran the risk of being overthrown by a very slight disturbance of equilibrium， and the mere instinct of self-preservation would force the Romans to devise some method of adjusting the rights and duties of foreigners， who might otherwise-and this was a danger of real importance in the ancient world —— have decided their controversies by armed strife. Moreover， at no period of Roman history was foreign trade entirely neglected. It was therefore probably half as a measure of police and half in furtherance of commerce that jurisdiction was first assumed in disputes to which the parties were either foreigners or a native and a foreigner. The assumption of such a jurisdiction brought with it the immediate necessity of discovering some principles on which the questions to be adjudicated upon could be settled， and the principles applied to this object by the Roman lawyers were eminently characteristic of the time. They refused， as I have said before， to decide the new Cases by pure Roman Civil Law. They refused， no doubt because it seemed to involve some kind of degradation， to apply the law of the particular State from which the foreign litigant came. The expedient to which they resorted was that of selecting the rules of law common to Rome and to the different Italian communities in which the immigrants were born. In other words， they set themselves to form a system answering to the primitive and literal meaning of Jus Gentium， that is， Law common to all Nations. Jus Gentium was， in fact， the sum of the common ingredients in the customs of the old Italian tribes， for they were all the nations whom the Romans had the means of observing， and who sent successive swarms of immigrants to Roman soil. Whenever a particular usage was seen to be practised by a large number of separate races in common it was set down as part of the Law common to all Nations， or Jus Gentium. Thus， although the conveyance of property was certainly accompanied by very different forms in the different commonwealths surrounding Rome， the actual transfer， tradition， or delivery of the article intended to be conveyed was a part of the ceremonial in all of them. It was， for instance， a part， though a subordinate part， in the Mancipation or conveyance peculiar to Rome. Tradition， therefore， being in all probability the only common ingredient in the modes of conveyance which the jurisconsults had the means of observing， was set down as an institution Juris Gentium， or rule of the Law common to all Nations. A vast number of other observances were scrutinised with the same result. Some common characteristic was discovered in all of them， which had a common object， and this characteristic was classed in the Jus Gentium. The Jus Gentium was accordingly a collection of rules and principles， determined by observation to be common to the institutions which prevailed among the various Italian tribes.

　　The circumstances of the origin of the Jus Gentium are probably a sufficient safeguard against the mistake of supposing that the Roman lawyers had any special respect for it. It was the fruit in part of their disdain for all foreign law， and in part of their disinclination to give the foreigner the advantage of their own indigenous Jus Civile. It is true that we， at the present day， should probably take a very different view of the Jus Gentium， if we were performing the operation which was effected by the Roman jurisconsults. We should attac