.

      The change from the Republic to the Principate introduced no very sudden alterations in the sources of law or the methods of procedure. Both, as we shall see, were supplemented by new creations; but up to the time of Gaius it was possible to appeal to the Republican system as the one that underlay the legal life and the judicial organization of Rome ^{Ref. 132}. All that was added by the Principate was in the nature of an excrescence—one that was probably healthy in its effects, in spite of the fact that it does seem to have limited to a certain extent the creative activities of juristic thought. The birth of the Principate was not conditioned by strictly legal necessities. There seems to have been little sense that a single controlling force was needed for the guidance of the law of Rome, Italy, and the provinces. The justification for the Principate was found in the fact that a single controlling power was necessary for the command of the army and the routine administration of the provinces. But it was impossible to create such a power without bringing it into some contact with every department of the State. The guidance of legislation and judicature by an individual will was a necessary outcome of the new order of things; and it is possible that this guidance was needed. There is a stage in the history of law where liberty of interpretation may lead to perplexing uncertainty, and there is a stage in the history of any national judicial organization where certain radical methods are necessary to adapt it to new needs. The Principate gave a definiteness to law, but a definiteness that was in no sense illiberal. On the contrary, it prevented law from being narrowly Roman as effectually as it checked it from recklessly absorbing foreign elements. It adapted law to provincial needs by expanding, but not impairing, its national character. At the same time it widened the scope of jurisdiction by methods which we shall soon describe—methods which seem to have increased the efficiency at least of the civil courts at Rome, and which brought the provincial world into closer judicial relations with the capital. The changes effected both in legislation and in jurisdiction were gradual

      and progressive; and, though they were from a formal point of view initiated by the will of individual monarchs, it is important to remember that, at Rome as elsewhere, monarchical power is the outcome of the concurrence of many individual wills. For the sake of convenience we are accustomed to treat the Princeps as the chief source of law and the chief influence on jurisdiction. Sometimes a purely personal power of this type may have been realized for a while, although when so realized it always had a flavour of tyranny ^{Ref. 133}. But as a rule, when we think of the Princeps as a source of law and justice, we should be thinking of his judicial advisers and assessors. The trained jurist still plays a leading part in legal progress. His control of the Princeps, and the Princeps’ control of him, must both be taken into account, although the actual extent of the respective influences—of the administrator over the jurist and of the jurist over the administrator—can never be determined for any given act or for any given moment of time.

      A division of power of this type is perhaps common to all monarchies. But in the Roman Principate, which was not technically a monarchy, we find it expressed in yet another way—a way which is of more importance theoretically, although perhaps of less practical import. It is expressed in the form that the Princeps is merely the ‘extraordinary magistrate’ of a Republican Constitution. By an ‘extraordinary magistracy’ is meant a magistracy formed by an accumulation of functions, each of which is usually exercised by a particular magistrate. The chief powers with which the Princeps was invested were the Proconsulare Imperium conferred by the Senate, and the Tribunicia Potestas conferred on a recommendation of the Senate in a formal meeting of the People. The Proconsulare Imperium was technically valid only outside the limits of Italy; but, as it was absolutely necessary that the Princeps should possess Imperium within Rome, he was specially exempted from losing his Imperium by his presence within the city. The effect of this exemption probably was to create for the Princeps a kind of consular Imperium in Rome and Italy. But even this device was not sufficient to secure for him the authority which he required as a moderator of the whole State. The Proconsulare Imperium and the Tribunicia Potestas required to be supplemented by a number of separate powers conferred by special grants. These grants must originally have been made by special laws and decrees of the Senate that were passed at various times; but the practice seems soon to have been adopted of embodying them in a single enactment, which was submitted to the formal assent of the People at the time when the Proconsulare Imperium and the Tribunicia Potestas were conferred. A fragment of such an enactment is the extant Lex or Senatusconsultum which enumerates powers conferred on the Emperor Vespasian at his accession ^{Ref. 134}. The rights of the Princeps enumerated in this document are of a very heterogeneous kind—they include the powers of making treaties, extending the pomerium of the city, commending candidates for office, and issuing edicts as interpretations of law, human and divine; and, important as they are, they have no direct connexion with either the Proconsulare Imperium or the Tribunicia Potestas. Some of the most imposing powers of the Princeps were dependent on neither of these two sources, but were contained only in this general Lex; and as fresh prerogatives were added to the Principate, the Lex would grow in bulk and importance. Some development of this kind may account for the fact that Gaius and Ulpian both speak of the Princeps receiving his Imperium through a Lex ^{Ref. 135}. Such an expression could not have been used of the early Principes; for the Proconsulare Imperium was received through a decree of the Senate; but it is possible that in the course of time the general Lex, as enumerating the majority of the prerogatives of the Princeps, came to overshadow the other sources of his authority.

      Since the authority of the Princeps was built up in this gradual and unsystematic way, it is quite impossible for the modern inquirer to determine with precision the sources of the exercise of his different powers. But a rough estimate may be made of five distinct kinds of prerogative and of the activities flowing from each. (1) With the Imperium were connected the control of the army and the provinces, the right of declaring war and of making treaties, the power of conferring Roman citizenship or Latin rights, civil and criminal jurisdiction, and the general power of legal interpretation. (2) The Tribunician Power, besides making the Princeps sacrosanct, gave him the right, exercised during the earlier period of the Principate but afterwards neglected, of initiating measures in the Assembly of the Plebs, and also the right of transacting business with the Senate, although this second right was extended by special grants. The power of veto, inherent in the Tribunicia Potestas, gave the Princeps a control over all the other magistrates of the State, enabled him to exercise over the jurisdiction of the Senate a power akin to that of pardon, and probably formed the basis of much of his appellate jurisdiction. (3) Two of the Principes, Claudius and Vespasian, were invested with the temporary office of censor, and Domitian declared himself censor for life. His example was not followed by succeeding rulers; but the most important of the functions of the censors—the revision of the lists of Senators and Knights—continued to be a part of the admitted prerogatives of the Princeps. Akin to this right was that of creating Patricians, which had been conferred by law on Caesar and Augustus, had been exercised by Claudius and Vespasian as censors, and finally became a right inherent in the Principate itself. (4) The Princeps, besides being a member of all the great religious colleges, was, as Pontifex Maximus, the official head of the state-religion, and was invested by law with the power of executing ordinances which were to the interest of the religious life of the community ^{Ref. 136}. (5) Supplementary powers, which cannot be described by a common name or connected with any definite office, were granted to the Princeps. Some of these were means by which his control over the magistrates and the Senate was increased. Such were the rights of securing the election of certain candidates for office by means of a recommendation (Commendatio), and of exercising powers in relation to the Senate superior to those possessed by the other magistrates.

      An authority thus endowed could not fail to exercise a strong directing influence on the sources of law and the methods of procedure. The influence asserted itself from the first; yet for at least two centuries there was always a formal, and sometimes a real recognition of the theory on which the