Foreign Mercenaries
Adjutants of the Legion

It was an innovation—­hazardous beyond doubt even in the view of its author—­to which the untrustworthy character of the cavalry furnished by the subjects compelled him,(34) that Caesar for the first time deviated from the old Roman system of never fighting with mercenaries, and incorporated in the cavalry hired foreigners, especially Germans.  Another innovation was the appointment of adjutants of the legion (-legati legionis-).  Hitherto the military tribunes, nominated partly by the burgesses, partly by the governor concerned, had led the legions in such a way that six of them were placed over each legion, and the command alternated among these; a single commandant of the legion was appointed by the general only as a temporary and extraordinary measure.  In subsequent times on the other hand those colonels or adjutants of legions appear as a permanent and organic institution, and as nominated no longer by the governor whom they obey, but by the supreme command in Rome; both changes seem referable to Caesar’s arrangements connected with the Gabinian law.(35) The reason for the introduction of this important intervening step in the military hierarchy must be sought partly in the necessity for a more energetic centralization of the command, partly in the felt want of capable superior officers, partly and chiefly in the design of providing a counterpoise to the governor by associating with him one or more colonels nominated by the Imperator.

The New Commandership-in-Chief

The most essential change in the military system consisted in the institution of a permanent military head in the person of the Imperator, who, superseding the previous unmilitary and in every respect incapable governing corporation, united in his hands the whole control of the army, and thus converted it from a direction which for the most part was merely nominal into a real and energetic supreme command.  We are not properly informed as to the position which this supreme command occupied towards the special commands hitherto omnipotent in their respective spheres.  Probably the analogy of the relation subsisting between the praetor and the consul or the consul and the dictator served generally as a basis, so that, while the governor in his own right retained the supreme military authority in his province, the Imperator was entitled at any moment to take it away from him and assume it for himself or his delegates, and, while the authority of the governor was confined to the province, that of the Imperator, like the regal and the earlier consular authority, extended over the whole empire.  Moreover it is extremely probable that now the nomination of the officers, both the military tribunes and the centurions, so far as it had hitherto belonged to the governor,(36) as well as the nomination of the new adjutants of the legion, passed directly into the hands of the Imperator; and in like manner even now the arrangement