The Senatus Consults also formed a source of law under the republic. That a senates consultum in the time of Gains (i. 4) should have the force of law (vicem legis optinet), may be easily admitted ; but Gains in this passage appears to be referring not only to such senatus consults as had been passed under the empire, but to the senatus consults generally as a source of law. Probably the senate gra dually came to be considered in some de gree as the representative of the curiae, and its consults, in many matters relating to administration, the care of religion, the aerarium, and the administration of the provinces, had the full effect of laws. It does not seem as if the Romans themselves had a very clear notion of the way in which the senate came to exercise the power of legislation ; but they imagined that it arose of necessity with the increas ing population of the state and the in crease of public, business. The senate thus became an active administrating body. and, as an easy consequence, that which it enacted (constituit) was observed, and this new source of law was termed Senutus Consultum (Dig., i., tit. 2). It seems probable that the senate began to exercise the power of making senates consults after the passing of the Hortensia Lex, though it is not pretended that the Hortensia Lex or any other Lex gave this power to the senate. No senatus consulta are recorded as designated by the names of magistrates, till the time of Augustus, a circumstance which seems to show that whatever binding authority senates con suite might have acquired under the Re public, they were not then viewed as laws properly so called. But from the time of Augustus, the titles of senates consults frequently occur ; their names, like those of most of the leges, were derived from the consuls, as S. C. Velleianum, Pegasi anum, Trebellianum, &c., or of the em peror who proposed them, as S. C. Clau dianum, Neronianum, &c., or they were said to be made " auctore Principe," or "ex auctoritate Principis." The exprea• sion applied to the senate, so enacting, was " censere." (Gains, i. 47.) Special consults were sometimes passed for the purpose of explaining or rendering effec tual previous leges.
A new source of law was supplied by the Edicts of those magistrates who bad the Jug Edicendi, but mainly by the praetors, the praetor urbanus and the praetor peregrinus. The edicts of the praetor urbanus were the most important. The body of law which was formed by the Edicts is accordingly sometimes called Jus Praetorium, which term however might be limited to the Edicta of the praetors, as opposed to those of the curule aediles, the tribunes, censors, and ponti fices. The name Jus Honorarium, as opposed to Jus Civile, comprehends the whole body of edictal law ; and the name Honorarium was given to it, apparently because the Jus Edicendi was exercised only by those magistrates who had the Honores. Jus Civile in its larger sense comprehended all the law of any given nation ; but the Jus Civile Romanorum, as opposed to the Honorarium, consisted of Leges, Plebiscite, Senatus Consults, to which, under the empire, were added the Decreta Principum and the Auctoritas Prudentium. The Honorarium Jus was introduced for the purpose of aiding, sup plying, and correcting the defects of the Jus Civile Romanorum in its limited sense. (Dig., i., fit. 1, s. 7.) The nature of the Roman Edictal Law is explained at the end of the article EQUITY.
With the establishment of the Imperial Constitution begins a new epoch in the Roman law. The loges of Augustus and those of his predecessor had some in fluence on the Jus Privatum, though they did not affect the fundamental principles of the Roman law. A Lex Julia came into operation, B.C. 13, hut it is better known as the Lex Julia et Papia Poppaea, owing to the circumstance of another lex of the same import, but less severe in its provisions, being passed as a kind of supplement to it in the consulship of M.
Papius Mutilus and Q. Poppaeus Secun dus, A.D. 9. This law had for its object the encouragement of marriage, but it contained a great variety of provisions. A Lex Julia de Adulteriis, which also contained a chapter on the dos, is of un certain date, but was probably passed be fore the former Lex Julia came into operation. Several Leges Juliae Judi ciariae are also mentioned, which related both to Judicia Publica and Privata, and some of which may probably belong to the time of the dictator Ciesar.
The development of the Roman law in the Imperial period was little affected by direct legislation. New laws were made by Senatus Consulta, and subse quently by the Constitutiones Principum ; but that which gives to this period its striking characteristic is the effect pro duced by the Responsa and the writings of the Roman jurists.
So long as the law of religion or the Jus Pontificium was blended with the Jus Civile in its limited sense, and the knowledge of both was confined to the patricians, jurisprudence was not a pro fession. But with the gradual separation of the Jus Civile and Pontificium, which was partly owing to the political changes by which the estate of the plebeians was put on a level with that of the patricians, there arose a class of persons who are designated as Jurisperiti, Jurisconsulti, Prudentes, and by other equivalent names. Of these jurisconsulti the earliest on re cord is Tiberius Coruncanius, a plebeian Pontifex Maximus, and consul B.C. 280: he is said to have been the first who pro fessed to expound the law to any person who wanted his assistance ; he left no writings, but many of his Responsa were recorded. Tiberius Coruncanius had a long series of successors who cultivated the law, and whose responsa and writings were acknowledged and received as a part of the Jus Civile. The opinions of the jurisconsulti, whether given upon questions referred to them at their own houses, or with reference to matters in litigation, were accepted as the safest rule by which a judex or an arbiter could be guided. Accordingly, the mode of pro ceeding, as it is described by Pomponius, is perfectly simple ; the judices in difficult cases took the opinion of the jurisconsulti, who gave it either orally or in writing. Augustus, it is said, gave the responsa of the jurists a different character. Before his time, their respousa, as such, could have no binding force, and they only in directly obtained the character of law by being adopted by those who were em powered to pronounce a sentence. Au gustus gave to certain jurists the respou dendi jus, and declared that they should give their responsa " ex ejus auctoritate." In the time of Gaius (i., 7) the Responsa Prudentium had become a recognised source of law ; but he observes that the responsa of those only were to be so con sidered who had received permission to make law (jura condere); and he adds that if they all agreed, their opinion was to be considered as law; if they disagreed, the judex might follow which opinion he pleased. The matter is thus left in some obscurity, and, for want of more precise information, we can only conjecture what was the precise way in which these li censed jurists under the empire were em powered to declare the law. It is how ever clear, both from the nature of the case and the statement of Gaius, that their functions were limited to exposition, or to the declaration of what was law in a given case, and that they had no power to make new rules of law as such ; fur ther, the licensed jurists must have formed a body or college, for otherwise it is not possible to conceive how the opinions of the majority could be ascertained on any given occasion.