Theoretically such a commander might always be deposed by the Roman people, acting through its Senate.  In reality he was master of the situation.  If he was ever deposed, or if a new commander was ever appointed, it was by the army.  If he proved a tyrant, there was no other means of getting rid of him than by the army, unless it were by assassination.  At such times the Senate might make a show of naming the successor, and the army might make a show of agreeing with the Senate, but such expressions, as Tacitus repeats, were “empty and meaningless words.”  The madman Caligula had been assassinated.  When, four years after our date, Nero was compelled to flee from his palace and was persuaded into committing suicide, it was because the soldiers had declared against him and had elected another.

The vast powers of the emperor had come into the hands of one man simply because the republic had been found incompetent to handle its empire, whether from a military or a financial point of view.  It managed neither so consistently nor so honestly as did the individual.

The emperor, then, by a constitutional fiction, was an officer of the commonwealth, commanding its forces, not only with the freedom of action which Rome had always allowed to its experts in dealing with the enemy, but with that freedom greatly enlarged, and with a tenure of the office perpetually renewed.

But to him that hath shall be given—­especially if he is in a position to insist on the gift.  The emperor’s military authority, his position as governor of provinces, could not alone rightfully qualify him to control Rome itself, with its laws, its magistrates, its domestic and provincial policy.  Theoretically the Roman emperor never did control these matters.

In practice he did with them very much as he chose.  If he seriously wished a certain course to be followed, a certain law to be passed or abolished, even a certain man to be elected to an office, it was promptly done.  But how could he thus perpetually interfere and yet appear to remain a constitutional officer?  Not through the mere obsequiousness of every one concerned, including the Senate.  That would be too transparent, clumsy, and invidious.  It was necessary that he should possess some adequate appearance of real authority, and he was therefore ingeniously invested with that authority.  It was thus.  There were under the commonwealth certain annual officers of wide and rather indefinite powers called “tribunes of the commons.”  These persons could veto any measure which they declared to be in opposition to the interests of the people.  They could also summon the Senate, and bring proposals before it.  Meanwhile their persons were “sacrosanct,” or inviolable, during their term of office.  Here lay the opportunity.  The emperor was invested by the Senate with these “powers of the tribune.”  He was not actually elected a tribune, for the office was only annual and could not be held along with any