The term ‘‘sources of law,’’ has two senses (cf. Johnston 1999: 1). The first is a practical question, better expressed in terms of‘‘transmission’’ than ‘‘sources’’: how do we, as historians, recover our knowledge of the law? The answer, easier to state than to implement given the multiplicity of sources, comprises the writers of literature, legal texts, inscriptions, papyri, and so on, on which we base our knowledge (O. Robinson 1997: 54-78). In reading these sources, we must always be alert to the agendas, whether overt or hidden, that they contain. This is especially true of literary texts, which often describe legal processes, in anecdotes expressing the writer’s judgment, in matters not directly to do with the law; they were not written to tell us about the law, but with concerns of their own. An example is the story of the emperor Claudius, who was extremely devoted to hearing legal cases and did it with such disregard for proper procedure that on one occasion an infuriated defendant, a Roman knight, hurled his sharpened pen and writing tablets at the emperor, badly cutting his cheek (Suet. Claud. 15). Another anecdote shows Augustus as judge, questioning a man accused of parricide in such a way that the defendant would have to insist on his own guilt in order to be condemned: ‘‘You surely did not kill your father?’’ (Suet. Aug. 33). Both stories are told in order to illustrate the character of the main protagonists - Augustus conscientious and lenient, Claudius willful and stupid - rather than to make a legal point. They are evidence, however, for the emperor’s role in jurisdiction.
An especially important source of information is inscriptions, either put up by imperial instruction in order to publicize the law or by successful petitioners who were anxious to record decisions in their favor and the services of the individuals who had secured them - that is to say that these too have their agendas, in the need to secure publicity. There are papyrus and other records of legal proceedings, which are interesting because they may take us to parts of the empire beyond the normal reach of the central government and into the domain of local law; and many individual documents in the class known as negotia (business transactions): agreements, leases, and contracts of different sorts. The main single source is of course the massive compilations of extracts made by jurists, to which we shall return.
The question of the sources of law in its second sense - what, in the Romans’ view, gave authority to the law - can most easily be addressed as a law student in the later second century would address it, from a standard textbook. The opening sentences of Gaius’ Institutes go straight to the heart of the matter. The sources of law are as follows: in the first place are laws ( leges) and plebiscites; then there are senatusconsulta, imperial edicts and the edicts of other magistrates, especially the praetors and aediles; and the opinions of those jurists who were permitted to ‘‘establish’’ it (the Latin word is condere). His formulation is echoed by the early third-century jurist Papinian: ‘‘the civil law (ius civile) is that which comes in the form of statutes, plebiscites, senatus consulta, imperial decrees, or authoritative juristic statements’’ (D. 1.1.7).
From the point of view of the authority of the law, it does not matter that Gaius and Papinian were giving a composite picture as it had developed to their own day, since Roman law was cumulative, and in all the forms which they mentioned had left some law that was still in active use. For example, Gaius explains the historical distinction between statute laws and plebiscites, observing that the latter were given the status of laws by the Lex Hortensia (of 267 bce). By Gaius’ time, the distinction was a matter of history only. It was still the case, however, that some of the ‘‘laws’’ that he and his contemporary jurists had to deal with were in fact plebiscites. The Lex Aquilia, of the later third century bce, concerned liabilities and remedies for damage to property, an extremely important subject. It merits an entire title in the Digest, in the first extract of which Ulpian notes the historical point that the ‘‘law,’’ which superseded all previous laws, was in fact a plebiscite, on a motion introduced by a tribune (9.2.1).
Statute law, in whatever form, was uncommon under the Roman Empire. After the many ‘‘Leges Iuliae’’ and others introduced or instigated by Augustus on various subjects (a sort of Indian summer of statute legislation), few statutory leges emerged from the Roman assemblies. Those that did, tended to reflect the political and dynastic needs of the ruling house and were often ceremonial in character, such as the series of laws setting out the posthumous honors to be paid to the princes Gaius and Lucius in 5 ce, and to Germanicus and Drusus after their premature deaths in 19 and 23 ce respectively. The law of 19, previously known in part and recently supplemented by one of several spectacular discoveries of inscriptions from Spain, has been somewhat over-interpreted because of its apparent reference to reforms in the procedures for electing consuls and praetors, but in its complete version it emerges as an essentially ceremonial - though very interesting - enactment (Jones 1955: 9-21; Gonzalez 1984). After this, the list of leges promulgated by the Roman people peters out very quickly. The best known is the so-called Lex de Imperio Vespasiani (‘‘Law Concerning the Imperial Power of Vespasian’’) of 70 ce, part of which survives in a fine bronze inscription now displayed in the Palazzo dei Conservatori at Rome, recording with precedents the concatenation of powers bestowed upon Vespasian upon his accession to the imperial office; whether it is taken to be ceremonial or substantive legislation depends on the view taken of the institutions of the early principate (Brunt 1977b). The last statutory legislation issued by the people is from the time of Nerva in 97 ce, but existing laws, many of them very ancient, continued to underlie the legal processes of the Roman Empire.
It is evident from the law of 19 honoring Germanicus, that its origin was a resolution of the Senate inviting legislation from the people, and this raises the next item in Gaius’ list of sources, decrees of the Senate. So partisan was the role of the Senate in the later republic that it could hardly then have been claimed as a legal authority by a conscientious jurist. Under the empire, however, despite complaints in some quarters of its loss of political liberties, the legal authority of the Senate was increased, through its relations with the people in the way we have just seen, and with the emperors (Talbert 1984: 431-59). We find the Senate issuing regulatory provisions in the form of senatus consulta, on matters such as public games at Syracuse (Tac. Ann. 15.49), the establishment of a market in north Africa (Riccobono, FIRA2, I, No. 47), and the cost of gladiators in the provinces (FIRA2, I, No. 49: Oliver and Palmer 1955). Some senatus consulta, which were often, but not always, responses to an imperial request for legislation, had a permanent effect upon important issues, such as the senatus consultum Claudianum on the marriage of partners of free and slave status, and the senatus consulta Orfitianum and Tertullianum on the inheritance and testamentary rights of women. The s. c. Claudianum, a set of regulations framed, ironically, by Claudius’ freedman Pallas, was not repealed (through disuse) until the time of Justinian.
Until the emergence of the emperors as lawgivers, Roman legal development owed more to the implementation and adaptation of existing rules than to substantive change in the law. This was done by the interventions of magistrates in the judicial process, and especially the Praetor’s Edict. This was the annual statement by which the urban praetor (also the praetor peregrinus in matters concerning resident aliens, and the aediles in matters affecting the markets) announced his forthcoming policy in the administration of the law - what types of case he would hear, what defenses he would admit, what exceptions he would allow, and so on. Each year the praetor would review the policy of his predecessor, accepting arguments and grounds of procedure that had been found satisfactory and rejecting or reviewing those that had not (Watson 1974b).
Praetorian jurisdiction was a cumbersome procedure, but it allowed for the application of the law to be changed even when the law itself was not. The most interesting example of this is the ‘‘legal fiction” whereby the prohibition of a noncitizen from taking legal action against a citizen was circumvented by the ‘‘fiction’’ that the non-citizen was in fact a citizen, a counterfactual assertion that allowed the law to develop in the interests of a broader conception of justice. Another was the procedure of ‘‘restoration’’ {restitutio in integrum), whereby under certain circumstances - if a victim had been unable to reach a court to defend his interests, for example, or could claim intimidation or fraud - a praetor could set aside a legal transaction in the interests of justice. A comical but still instructive example of the praetor’s powers is cited by Aulus Gellius {Gel. 20.1.13) from the writings of the Augustan jurist Labeo on the Twelve Tables. An offensive Roman by the name of L. Veratius was in the habit of accosting free Romans and slapping them in the face. He would then take 25 asses from a slave following him and give them to the person he had insulted, this being the fine, by now of no value, laid down by the Twelve Tables. The praetors added to their Edict the provision that the question of damages in such a case would be henceforth submitted to a board of ‘‘recoverers’’ {recuper-atores) for appraisal, and this became the law in future. And to take an example from statute law, almost the whole title in the Digest relating to the Lex Aquilia mentioned earlier consists of extracts from juristic commentaries on the edicts of the praetors and provincial governors {D. 9.2.1-57). The law itself was neither changed nor repealed, but was progressively modified in its application by magisterial edict and juristic interpretation.
In the time of Hadrian, the Edict was consolidated as a statement of private law by the great jurist Salvius Julianus. It was the subject of the massive commentaries by Gaius, Ulpian, and others mentioned earlier, and in its organization of subject matter underlies the private law sections of the Theodosian Code, the Codex Justinianus, and the Digest itself. The text of the Edict, which does not survive in its complete state, was reconstituted by Otto Lenel from the references to it made by the commentaries cited in the Digest and other sources.
Long before its codification by Julianus, the Edict had been superseded by a new set ofprocedures deriving from the concentration ofmagisterial powers in the hands ofthe Roman emperors. The emperor was now expected to remedy deficiencies in the law by changing it substantively, and he did so by all the means mentioned by Gaius - by decree, edict, and letter, all of which became known collectively by the single term, ‘‘constitution.’’ Modern discussions are often content to describe them by the single term ‘‘pronouncement,’’ or even ‘‘law,’’ but they differ in character. Decrees {decreta) are strictly understood as legal rulings arising from the emperor’s role as judge. Edicts were open communications directly addressed to the people at large or to individual communities, while letters were addressed to governors with instructions to enforce them within their jurisdictions. The best-known example of legislation by edict is probably the set of edicts issued by Augustus to the province of Cyrene on various aspects of local jurisdiction {Sherk 1984: 127-32), while the tenth book of Pliny’s letters, those exchanged with Trajan from the province of Bithynia, provides an excellent example of lawmaking by letters addressed to a provincial governor {Sher-win-White 1966: 525-8). Trajan’s reply to Pliny on the subject of the trial and punishment of Christians, for instance, is founded on an assertion of sound legal principles - only actual crimes are to be punished, alleged Christians are not to be sought out, and anonymous denunciations are not to be admitted {Pliny Ep. 10.96-7).
Gaius’ claim, with which Ulpian agreed (D. 1.4.1), that imperial edicts possessed the force of law because they were an exercise of his imperium that was bestowed on him by law has been criticized as unsatisfactory. However, the formulation is only meant to provide an underpinning in constitutional theory for a right that the emperor was clearly understood to possess. Ulpian offered an enlargement of the theory, in the form of the proposition, ‘‘anything decided by the emperor has the force of law’’ (D. 1.4.1 pr.). This is not quite so bald a statement as it looks. Ulpian defined the categories of authoritative imperial pronouncements as whatever the emperor had decided ‘‘by letter over his signature or decreed on judicial investigation, or pronounced in an interlocutory manner or prescribed in an edict;’’ in sum, ‘‘what we commonly call constitutions.’’ The word used for ‘‘decided,’’ placet, is the formal word for a decision taken in due order by a properly constituted body, and there could hardly be any doubt that the emperor was such. We have also to take into account the expectation in every area of Roman life, that when serious decisions were taken, they were taken seriously and with relevant advice. The emperor’s rulings possessed legal force because of the emperor’s authority as properly exercised, namely with the advice of jurists. For the whole process of change and innovation in the law, whether this was done by procedural intervention by praetors or by substantive changes brought in by emperors, the contribution of jurists was essential.