Marcus. The hostilities of the
barbarians provoked the resentment of that philosophic monarch, and, in
the prosecution of a just defence, Marcus and his generals obtained
many signal victories, both on the Euphrates and on the Danube. [29] The
military establishment of the Roman empire, which thus assured either
its tranquillity or success, will now become the proper and important
object of our attention.

[Footnote 29: Dion, l. lxxi. Hist. August. in Marco. The Parthian
victories gave birth to a crowd of contemptible historians, whose memory
has been rescued from oblivion and exposed to ridicule, in a very lively
piece of criticism of Lucian.]

In the purer ages of the commonwealth, the use of arms was reserved for
those ranks of citizens who had a country to love, a property to defend,
and some share in enacting those laws, which it was their interest as
well as duty to maintain. But in proportion as the public freedom was
lost in extent of conquest, war was gradually improved into an art, and
degraded into a trade. [30] The legions themselves, even at the time
when they were recruited in the most distant provinces, were supposed
to consist of Roman citizens. That distinction was generally considered,
either as a legal qualification or as a proper recompense for the
soldier; but a more serious regard was paid to the essential merit
of age, strength, and military stature. [31] In all levies, a just
preference was given to the climates of the North over those of the
South: the race of men born to the exercise of arms was sought for in
the country rather than in cities; and it was very reasonably presumed,
that the hardy occupations of smiths, carpenters, and huntsmen, would
supply more vigor and resolution than the sedentary trades which are
employed in the service of luxury. [32] After every qualification of
property had been laid aside, the armies of the Roman emperors were
still commanded, for the most part, by officers of liberal birth and
education; but the common soldiers, like the mercenary troops of modern
Europe, were drawn from the meanest, and very frequently from the most
profligate, of mankind.

[Footnote 30: The poorest rank of soldiers possessed above forty pounds
sterling, (Dionys. Halicarn. iv. 17,) a very high qualification at a
time when money was so scarce, that an ounce of silver was equivalent
to seventy pounds weight of brass. The populace, excluded by the ancient
constitution, were indiscrimin