There was one source, however, most distinctively expressive of the character of the Principate, which found no expression in legal enactments. The military oath (_sacramentum_), which during the closing years of the Republic was tending to become a bond of personal allegiance between a legion and its chief, was naturally taken in the Principate by the whole army to its sole commander.[1592] But on the very first transference of the throne a new departure was made. At the accession of Tiberius the oath of fealty was taken voluntarily by the civil orders;[1593] it was administered by provincial governors and was renewed twice a year, on the first of January and on the anniversary of the Emperor’s accession.[1594] The fact that a soldier’s oath bound the whole Roman world was the fittest expression of the military character of the new despotism. A classification of the Emperor’s powers in detail, with an attempt to deduce each of them from a prerogative conferred on him at his accession, is rendered difficult by the facts that no Roman lawyer cared or dared to evolve a complete theory of the Imperial constitution, and that here, as in so many other departments of Roman history, we are dealing with an office which, as it grew, gradually absorbed into itself fresh spheres of influence. The Principate, in fact, finally absorbed the state, and the only adequate formula for its authority which later jurists could find was that the people had committed its sovereign power to its delegate. But yet, when we examine the spheres of the Emperor’s activity, it becomes clear that, while some are connected with an _imperium_, others are attached more closely to the tribunician power, while others again are associated with the relics of Republican offices held by the Princeps, or flow from certain extraordinary rights conferred on him by statute. (i.) The first rights connected with the _imperium_ that strike our attention are those exercised in the military sphere—rights which, on a vast scale, reflect and extend the powers possessed by the _imperator_ of the Republic. The Princeps has the right to raise levies,[1595] to nominate officers, and to confer military distinctions. In declaring war he has replaced the comitia of the centuries; and the statutory recognition of his right to conclude a treaty[1596] settled a vexed question of Republican procedure.[1597] This recognition of the federative power was not earlier than the reign of the first Claudius,[1598] but had already become a permanent element in the imperial authority by the accession of Vespasian. The right to extend the _pomerium_ of the city, which dates also from the reign of Claudius, is also found amongst the list of imperial prerogatives in 69 A.D.[1599]