There can be no doubt that Julius Cæsar would have ascended the throne of Rome as absolute imperator after his return from the Parthian expedition, and Octavian as well had it in his power to claim sovereignty without limitation of any kind, for the whole army and fleet were under his command; but he rested content with a more modest title and took the reins of government, not as imperator but as princeps. He did not found a monarchy but a diarchy, as it has been aptly styled, in which the power was to be permanently divided between the emperor and the senate. It was a compromise with the old republic, a voluntary constitutional limitation of the sovereign prerogative by which all the rights pertaining to the people and the senate--legislation no less than legal jurisdiction, the right of coinage no less than the levy of taxation, the disposal of the revenue and expenditure of the state, and finally (after the accession of Tiberius and ostensibly in compliance with a clause in the testamentary dispositions of Augustus), the appointment of magistrates--were to appertain, under well-defined rules, in part to the princeps and in part to the senate. The empire was to be elective, as the old Roman monarchy had been; the nomination to the throne was to proceed from the senate, but on the other hand the supreme command of the army and fleet was vested in the emperor in virtue of his proconsular authority, which extended over all parts of the empire outside the limits of the city of Rome. The legions were quartered in the provinces under his jurisdiction, while in those governed by the senate, with a few exceptions which soon ceased to be, all that the governors had at their disposal was a very moderate force of auxiliary troops. [Illustration: ROMAN TROPHIES]