A post-classical term defined by the Digest (i. 1, 10) as the knowledge of what is legally right and wrong (iusti atque iniusti scientia). The science of law is the one branch of Roman literature which had a purely national development. From an early date there were definite legal ordinances in Rome, and shortly after the expulsion of the kings a collection of leges regiae was made by a certain Papirius. These consisted of archaic customary laws of a strongly sacerdotal character, and arbitrarily attributed to individual kings (known as the Ius Papirianum). However, the foundation of the collective legal life of the Romans was primarily the well-known law of the Twelve Tables, B.C. 451-450. (See Twelve Tables.) This put an end to the want of a generally known law; for the knowledge of previous legal decisions, like the whole of the judicial procedure, had been hitherto kept in the exclusive possession of the patricians. The administration of the law remained as formerly in the hands of the patricians alone, for they kept from the plebeians all knowledge of the dies fasti and nefastii. e. the days on which legal proceedings might or might not be taken, as also the forms of pleading which were regularly employed (legis actiones). The latter were so highly important that the least infraction of them would involve the loss of the cause. This condition of things existed for a long time, until Appius Claudius Caecus drew up a calendar of the days on which causes could be pleaded, and a list of the forms of pleading. These were made public about B.C. 304 by his secretary, Gnaeus Flavius, after whom they were then called Ius Flavianum. By these means a knowledge of the law became generally attainable. It soon had eminent representatives among the plebeians in the persons of Publius Sempronius Sophus and Tiberius Coruncanius. In ancient days, however, the work of the jurists was purely practical. It was considered an honourable thing for men learned in the law (iuris periti) to allow people to consult them (consulere, hence iuris, or iure consulti) either in the Forum or at appointed hours in their own houses, and to give them legal advice (responsa). It was mainly by a kind of oral tradition that the knowledge of law was handed down, as the most eminent jurists allowed younger men to be present at these consultations as listeners (auditores or discipuli).
The beginning of literary activity in this department, as in others, dates from the Second Punic War. It begins with the earliest exposition of existing law. Sextus Aelius Catus published in B.C. 204 a work named Tripertita (from its being divided into three parts) or Ius Aelianum, which consisted of the text of the laws of the Twelve Tables together with interpretations, and the legal formulae for carrying on suits. From the middle of the second century it became common to make collections of the responsa of eminent jurists, and to use them as a source of legal information. Among others, Marcus Porcius Cato , the son of Cato the Elder, made a collection of this kind. In some families knowledge of the law was in a measure hereditary, as in those of the Aelii, Porcii, Sulpicii, and Mucii. A member of the last family, the pontifex Quintus Mucius Scaevola (died B.C. 82), was the first who, with the aid of the formal precision of the Stoic philosophy, gave a scientific and systematic account of all existing law, in his work, De Iure Civili. Servius Sulpicius Rufus, the contemporary and friend of Cicero, further advanced this new and more methodical treatment of law by his numerous writings and by training up pupils, such as Aulus Ofilius and Publius Alfenus Varus. The former rendered great assistance to Caesar in his scheme for forming the whole of the Ius Civile into a single code. Besides these there were several eminent jurists at the close of the Republic: Gaius Trebatius Testa, Quintus Aelius Tubero, Gaius Aelius Gallus , and Aulus Cascellius.
While under the Republic the learned jurist had held an inferior position to the orator in influence and importance, there is no doubt that under the Empire public eloquence became subordinate, and the position of the jurists was the most coveted and influential in the State, especially when Augustus decreed that the opinions of jurists authorized [p. 901] by the head of the State were to have the validity of law. It was from the jurists as advisers of the emperor that all legislation now proceeded. They had access to all the highest offices of the court and of the State. Accordingly men of the highest gifts and character betook themselves naturally to this profession, and even introduced into the laws an increased unity, consistency, and systematic order. Under Augustus two jurists were pre-eminent, Quintus Antistius Labeo and Gaius Ateius Capito, the founders of the two later schools, named, after their pupils Sempronius Proculus and Masurius Sabinus, the Proculiani and Sabini respectively. Labeo sought to extend his professional knowledge, while Capito held fast to the traditions of former jurists. A third school was that of the Cassiani, who took their name from the jurist Cassius Longinus (Pliny , Epist. vii. 24, 8), and represented a mean between the conservatism of Capito and the innovating spirit of Labeo.
The first scientific collection of laws was made under Hadrian by the Sabinian lawyer Salvius Iulianus, with his Edictum Perpetuum, a classified collection of the praetorian edicts from the times of the Republic. (See Edictum.) Sextus Pomponius, his somewhat younger contemporary, composed among other things a history of the law till the time of Hadrian.
Under the Antonines jurisprudence was able to claim a remarkable representative in the Asiatic Gaius, but it received its completion and conclusion in the first half of the third century A.D. through Aemilius Papinianus, Domitius Ulpianus, and Iulius Paulus. After their time there were no jurists of great and original capacity. In the fourth century literary activity revived again, but confined itself to the collection of legal authorities, especially that of imperial ordinances. Thus the Codex Theodosianus, finished in A.D. 438, contains an official record of all the enactments decreed by the emperors from the time of Constantine. Under Justinian I. (A.D. 527-565) the last and most complete Roman collection of laws was made, under the name of the Corpus Iuris Civilis (q. v.).
See Bach, Historia Iurisprudentiae Romanae (rev. by Stockmann, Leipzig, 1796); Bremer, Die Rechtslehrer und Rechtsschulen im rm. Kaiserreich (Berlin, 1868); Krger, Quellen und Lit. des rm. Rechts; and on the law language, Kalb, Das Juristlatein (Nrnberg, 1886).