Between Augustus and Diocletian the reign of the Severan emperors, particularly the promulgation of the Edict of Caracalla, the Constitutio Antonina, which extended Roman citizenship to almost all the free inhabitants of the empire, may be considered the turning-point of the tendency toward absolutism.[387] It broke finally and completely with the legal theory that the _populus Romanus_ was a paramount community within a complex of other similar and inferior communities. From that time on nearly all those who could possess rights and obligations at all, whether in regard to one another or to the state, were members of the paramount community, and the delegation of the _imperium_ to the _princeps_, which had until then been subject to the remote but still conceivable possibility of revocation, became irrevocable by the sheer impossibility of conceiving the _populus_ as acting in the only way the _populus_ could legally act, by direct vote when assembled in mass in the Campus Martius. In the period between Caracalla and Diocletian the vast political machine snapped at many points. Diocletian’s skill enabled it to go on for a considerable time, and yet the changes he instituted were administrative rather than social. Internally the new _populus Romanus_ took its form in the third century. A calculation of doubtful value makes the population of the empire at that time about 85,000,000.[388] Of these about half were slaves, _i.e._ at law not participants in the empire at all. The other half were nearly all _cives Romani_, Roman citizens, and it is the position of these _cives_ that now concerns us. Upon the _civis Romanus_ devolved the task of maintaining a frightfully expensive governmental machinery. The expense consisted in the fact that a huge army had to be maintained on what was practically a war footing all the time, because, as a matter of fact, war with the barbarians on the northern frontier and with the Parthians in the East was always going on. Compared with that, the expenses of the court itself, although considerable, were scarcely important; but an important item was the vast horde of civil employees which the execution of so tremendous a budget necessitated. Then the local civic centers, generally the remains of old independent communities, had an organization of their own that was partly ornamental, but in all circumstances costly. That is to say, a very large share of the available wealth of the empire was diverted into unproductive channels, since it was devoted to the purpose of maintaining a machinery not altogether necessary to guard that wealth.