A disciple of Ulpian’s was Herennius Modestinus, of whom 344 extracts are contained in the Digest. After Modestinus the lustre of Roman jurisprudence began to decline. (For a detailed account of the Roman jurists, see Roby’s Introduction to the Digest, chs. vi-xvi.)
Besides the sources of law enumerated by Gaius, the Institutes of Justinian (1, 2, 9 and 10) mention Custom or Usage, the source of consuetudinary or customary law (jus non scriptum, consensu receptum, moribus introductum). To this branch of law are referred, with other rules, the invalidity of donations between husband and wife, Dig. 24, 1, 1, the power of a paterfamilias to make a will for his filiusfamilias who dies before the age of puberty (pupillaris substitutio), Dig. 28, 6, 2 pr., and universal succession in Coemption and Adrogation, 3 § 82. See also 4 §§ 26, 27. We may suppose that Customary law, like Roman law in general, would fall into two divisions, jus civile and jus gentium, the former embracing what Roman writers sometimes speak of as mores majorum. Before the time of Gaius, however, most of Customary law must have been incorporated by statute, as in early times by the law of the Twelve Tables, or taken up into the edict of the praetor or the writings of the jurists, Cic. De Invent. 2, 22, 67; i.e. unwritten law must have changed its character and have been transformed into written law.
II. ON THE BRANCHES OF THE LAW.
§ 8. The whole of the law by which we are governed relates either to persons, or to things, or to actions; and let us first examine the law of persons.
§ 8. What are the leading divisions of law—what are the main masses into which legislation naturally breaks itself—what are the joints and articulations which separate the whole code into various subordinate codes, like the different limbs and members of an organic whole—what is the import of the Gaian division, adopted perhaps from previous writers, into jus personarum, jus rerum, jus actionum, or rather, to adhere to the classical phrases, jus ad personas pertinens, jus ad res pertinens, jus ad actiones pertinens?
By jus ad actiones pertinens, to begin with the easier part of the problem, there is no doubt that the inventor of the division intended to designate the law of PROCEDURE as opposed to the law of rights; the adjective code, to use Bentham’s phraseology, as opposed to the substantive code. There is as little doubt that in the Institutions of Gaius this design is not executed with precision, and that, instead of the law of procedure, the last portion of his treatise contains also to some extent the law of sanctioning rights, as opposed to the law of primary rights. (For the meaning of this distinction see Austin’s Jurisprudence, bk. 1.) Or perhaps we should say that the legislative provisions respecting Procedure have a double aspect: a purely formal aspect, so far as they give regularity and method to the enforcement of sanctioning rights; and a material aspect, so far as certain stages of procedure (e.g. litis contestatio and res judicata) operate like Dispositions or any other Titles to modify the substantive rights of the contending parties. Procedure, then, is treated of in these Institutions partly indeed in its formal character, but still more in its material character, i.e. so far as its incidents can be regarded as belonging to the substantive code.
It is more difficult to determine the principle of the other division, the relation of the law of Persons to the law of Things. They both deal with the rights and duties of persons in the ordinary modern acceptation of the word; why then, we may inquire, are certain rights and duties of persons separated from the rest and dealt with under the distinguishing category of jura personarum? It is not enough to say with Austin that the law of Things is the universal or general portion of the law, the law of Persons a particular and exceptional branch; that it is treated separately on account of no essential or characteristic difference, but merely because it is commodious to treat separately what is special and exceptional from what is general and universal. This answer furnishes no positive character of the law of Persons, but only the negative character of anomaly, i.e. of unlikeness to the larger portion of the law; but it would be difficult to show that the law of Persons is more exceptional, anomalous, eccentric, than the Civil dispositions as opposed to the Natural dispositions of the law of Things.
We must look to the details of the law of Persons, and observe whether its dispositions have any common character as contrasted with the dispositions of the law of Things. The law of Persons, in other words, the law of Status, classifies men as slaves and free, as citizens (privileged) and aliens (unprivileged), as paterfamilias (superior) and filiusfamilias (dependent). The law of Things looks at men as playing the parts of contractors or of neighbouring proprietors; in other words, the law of Persons considers men as UNEQUALS, the law of Things considers them as EQUALS: the one may be defined as the law of relations of inequality, the other as the law of relations of equality.
It may induce us to believe that the law of unequal relations and the law of equal relations is a fundamental division of the general code, if we consider how essential are the ideas of equality and inequality to the fundamental conception of law. If we ventured on a Platonic myth, we might say that Zeus, wishing to confer the greatest possible gift on the human race, took the most opposite and uncombinable things in the universe, Equality and Inequality, and, welding them together indissolubly, called the product by the name of political society or positive law.
The assumption will hardly be controverted, that in the relations of subject to subject, Positive law, like Ethical law, recognizes, as an ideal at least, the identity of the just (lawful) with the equal. Inequality, however, is no less essentially involved in positive law. We have seen that there is no right and no duty by positive law without a legislator and sovereign to whom the person owing the duty is in subjection. On the one side weakness, on the other irresistible power. Positive rights and duties, then, imply both the relation of subject to subject and the relation of subject to sovereign or wielder of the sanction, in other words, both the relation of equal to equal and the relation of unequal to unequal. It is the more surprising that Austin should apparently have failed to seize with precision this conception of the law of Persons, as he makes the remark, in which the whole truth seems implicitly contained, that the bulk of the law of Persons composes the Public, Political, or Constitutional code (jus publicum). Political society or government essentially implies subordination. It implies, on the one hand, sovereign power reposing in various legislative bodies, distributed, delegated, and vested in various corporations, magistrates, judges, and other functionaries; on the other hand, private persons or subjects subordinate to the sovereign power and to its delegates and ministers. The different forms of government are so many forms of subordination, so many relations of superior and inferior, that is, so many relations of unequals. Public law, then, is a law of Status, and the law of Persons or law of Status in the private code is the intrusion of a portion of the public code into the private code; or, in barbarous and semi-civilized legislations, the disfigurement of private law by the introduction of relations that properly belong to public law. For instance, the most salient institution of the ancient Roman law of Persons, the power of life and death over wife and child that vested in the father of the household, was the concession to a subject of an attribute that properly belongs to the sovereign or a public functionary. Another institution, slavery, placed one subject over another in the position of despotic sovereign. The relation of civis to peregrinus may be conjectured to have originally been that of patronus to cliens, that is to say, of political superior to political inferior.
Government or positive law has usually commenced in the invasion by the stronger of the (moral) rights of the weaker; but so necessary is inequality to equality, or subordination to co-ordination, that the (moral) crimes of ancient conquerors are regarded with less aversion by philosophic historians, as being the indispensable antecedents of subsequent civilization. The beginnings, then, of positive law have been universally the less legitimate form of inequality, inequality between subject and subject, leaving its traces in dispositions of the civil code: but the advance of civilization is the gradual elimination of inequality from the law, until little remains but that between magistrate and private person, or sovereign and subject. Modern society has advanced so far on the path of equalization, in the recognition of