The armies were now largely recruited with barbarians, who
numbered more than half the fighting strength and were esteemed the flower of
the Roman soldiery. Many of these hirelings showed an open contempt for their
employers, and sympathised with the enemies whom they were paid to fight.
Furthermore, each army, whatever its constituent elements, tended to be a
hereditary caste, with a strong corporate spirit, respecting no authority but
that of the general. The soldiers had no civic interests; but they had standing
grievances against the Empire. Any political crisis suggested to them the idea
of a mutiny led by the general, sometimes to obtain arrears of pay and
donatives, sometimes to put their nominee upon the throne.
The evil was an old
one, dating from the latter days of the Republic, when Marius, in the interests
of efficiency, had made military service a profession. But it was aggravated
under the successors of Diocletian, as the barbarian element in the armies increased
and the Roman element diminished. Its worst effects appeared in the years
406-407. The German inroads upon Italy and Gaul were then followed by the
proclamation of military usurpers in Britain and on the Rhine; the Roman West
was divided by civil war at the very moment when union was supremely important.
Hence the strange spectacle of the Visigoths, still laden with the spoils of
Rome, entering Gaul by invitation of the Empire to fight against imperial
armies.
