The task which devolved upon Caesar when he had resigned the triumvirate and the proconsular power which had been conferred on him in 43 BC, was to restore the republic and yet place its administration in the hands of one man, to disguise the monarchy, which he already possessed, under a constitutional form, to be a second Romulus without being a king. He still held the tribunician power which had been given him for life in 36 bc.

On January 16, in the year of the city 727, three days after Caesar had laid down his extraordinary powers, the Roman Empire formally began. Munatius Plancus on that day proposed in the senate that the surname Augustus should be conferred on Cesar in recognition of his services to the state. This name did not bestow any political power, but it became perhaps the most distinctive and significant name of the Emperor. It suggested religious sanctity and surrounded the son of the deified Julius with a halo of consecration.

The actual power on which the Empire rested, the imperium proconsulare, was conferred upon, or rather renewed for, Augustus (so we may now call him) for a period of ten years, but renewable after that period. This imperium was of the same kind as that which had been given to Pompeius by the Gabinian and Manilian laws. The Imperator had an exclusive command over the armies and fleet of the republic, and his “province” included all the most important frontier provinces. But this imperium was essentially military; and Rome and Italy were excluded from its sphere. It was therefore insufficient by itself to establish a sovereignty, which was to be practically a restoration of royalty, while it pretended to preserve the republican constitution. The idea of Augustus, from which his new constitution derived its special character, was to supplement and reinforce the imperium by one of the higher magistracies.

His first plan was to combine the proconsular imperium with the consulship. He was consul in 27 BC, and he caused himself to be re-elected to that magistracy each year for the four following years. The consular imperium, which he thus possessed, gave him not only a locus standi in Rome and Italy, but also affected his position in the provinces. For if he only held the proconsular imperium he was merely on a level legally with other proconsular governors, although his “province” was far larger than theirs. But as consul, his imperium ranked as superior (maius) over that of the proconsuls. He found, however, that there were drawbacks to this plan. As consul he had a colleague, whose power was legally equal; and this position was clearly awkward for the head of the state. Moreover, if one consul was perpetual, the number of persons elected to the consulship must be smaller; and consequently there would be fewer men available for those offices which were only filled by men of consular rank. The consuls too were regarded as in a certain way representative of the senate; and the Emperor, the child of the democracy, might prefer to be regarded as representative of the people. His thoughts therefore turned to the tribunate, which was specially the magistracy of the people. But it would have been more awkward to found supremacy in civil affairs on the authority of one of ten tribunes than on the powers of one of two consuls. Accordingly Augustus fell back on the tribunicia potestas, which he had retained, but so far seems to have made little use of.

In 23 BC he gave up his first tentative plan and made the tribunicia potestas, instead of the consulship, which he resigned on June 27, the second pillar of his power. The tribunician power was his for life, but he now made it annual as well as perpetual, and dated from this year the years of his reign. Thus in a very narrow sense the Empire might be said to have begun in 23 BC; in that year at least the constitution of Augustus received its final form. After this year, his eleventh consulship, Augustus held that office only twice (5 and 2 BC). Subsequent Emperors generally assumed it more than once; but it was rather a distinction for the colleague than an advantage for the Emperor

But the tribunicia potestas alone was not a sufficient substitute for the consulare imperium which Augustus had surrendered by resigning the consulate. Accordingly a series of privileges and rights were conferred upon him by special acts in 23 bc and the following years. He received the right of convening the senate when he chose, and of proposing the first motion at its meetings (ius primes relationis). His proconsular imperium was defined as “superior” (maius) to that of other proconsuls. He received the right of the twelve fasces in Rome, and of sitting between the consuls, and thus he was equalized with the consuls in external dignity (19 BC). He probably received too the ius edicendi, that is, the power of issuing magisterial edicts. These rights, conferred upon Augustus by separate acts, were afterwards drawn up in a single form of law, by which the senate and people conferred them on each succeeding Emperor. Thus the constitutional position of the Emperor rested on three bases : the proconsular imperium, the tribunician potestas, and a special law of investiture with certain other prerogatives.

MEANING OF THE NAME PRINCEPS

The title imperator expressed only the proconsular and military power of the Emperor. The one word which could have expressed the sum of all his functions as head of the state,—rex—was just the title which Augustus would on no account have assumed; for by doing so he would have thrown off the republican disguise which was essential to his position. The key to the Empire, as Augustus constituted it, is that the Emperor was a magistrate, not a monarch. But a word was wanted, which, without emphasizing any special side of the Emperor’s power should indicate his supreme authority in the republic. Augustus chose the name princeps to do this informal duty. The name meant the first citizen in the state—princeps civitatis—and thus implied at once supremacy and equality, quite in accordance with the spirit of Augustus’ constitution; but did not suggest any definite functions. It was purely a name of courtesy. It must be carefully distinguished from the title princeps senatus. The senator who was first on the list of the conscript fathers, and had a right to be asked his opinion first, was called princeps senatus; and that position had been assigned to Augustus in 28 BC. But when he or others spoke or wrote of the princeps, they did not mean “prince of the senate”, but “prince of the Roman citizens”. The Empire as constituted by Augustus is often called the Principate, as opposed to the absolute monarchy into which it developed at a later stage. The Principate is in fact a stage of the Empire; and it might be said that while Augustus founded the Principate, Julius was the true founder of the Empire.

Constitutional theory of the Principate.

According to constitutional theory, the state was still governed under the Principate by the senate and the people. The people delegated most of its functions to one man, so that the government was divided between the senate and the man who represented the people. In the course of time the republican forms of the constitution and the magisterial character of the Emperor gradually disappeared; but at first they were clearly marked and strictly maintained. The senate possessed some real power; assemblies of the people were held; consuls, praetors, tribunes, and the other magistrates were elected as usual. The Principate was not formally a monarchy, but rather a “dyarchy”, as German writers have called it; the Princeps and the senate together ruled the State. But the fellowship was an unequal one, for the Emperor, as supreme commander of the armies, had the actual power. The dyarchy is a transparent fiction. The chief feature of the constitutional history of the first three centuries of the Empire is the decline of the authority of the senate and the corresponding growth of the powers of the Princeps, until finally he becomes an absolute monarch. When this comes to pass, the Empire can no longer be described as the Principate.

The Princeps was a magistrate. His powers were entrusted to him by the people, and his position was based on the sovereignty of the people. Like any other citizen he was bound by the laws, and if for any purpose he needed a dispensation from any law, he had to receive such dispensation from the senate. He could not be the object of a criminal prosecution; this, however, was no special privilege, but merely an application of the general rule that no magistrate, while he is in office, can be called to account by any one except a superior magistrate. Hence the Princeps, who held office for life and had no superior, was necessarily exempted from criminal prosecution. If, however, he abdicated or were deposed, he might be tried in the criminal courts. And as Roman Law permitted processes against the dead, it often happened that a Princeps was tried in the senate after his death, and his memory condemned to dishonor, or his acts rescinded. The heavier sentence deprived him of the honor of a public funeral and abolished the statues and monuments erected in his name; while the lighter sentence removed his name from those Emperors, to whose acts the magistrates swore when they entered on their office. When a Princeps was not...