Bactria he subjugated the Parthians. It was thus, almost
certainly, that they lost their independence and became Persian
subjects. Competent enough to maintain themselves against the
comparatively small tribes in their near neighborhood, the Chorasmians,
Hyrcanians, Arians of Herat, Bactrians, and Sagartians, it was not
possible for them to make an effectual resistance to a monarch who
brought against them the entire force of a mighty empire. Cyrus had,
it is probable, little difficulty in obtaining their submission. It is
possible that they resisted; but perhaps it is more probable that their
course on this occasion was similar to that which they pursued when the
Macedonian conqueror swept across these same regions. The Parthians at
that period submitted without striking a blow. There is no reason to
believe that they caused any greater trouble to Cyrus.

When the Persian empire was organized by Darius Hystaspis into
satrapies, Parthia was at first united in the same government with
Chorasmia, Sogdiana, and Aria. Subsequently, however, when satrapies
were made more numerous, it was detached from these extensive countries
and made to form a distinct government, with the mere addition of the
comparatively small district of Hyrcania.40 It formed, apparently, one
of the most tractable and submissive of the Persian provinces. Except on
the single occasion already noticed, when it took part in a revolt that
extended to nearly one-half the empire, it gave its rulers no trouble;
no second attempt was made to shake off the alien yoke, which may indeed
have galled, but which was felt to be inevitable. In the final struggle
of Persia against Alexander, the Parthians were faithful to their
masters. They fought on the Persian side at Arbela; and though they
submitted to Alexander somewhat tamely when he invaded their country,
yet, as Darius was then dead, and no successor had declared himself,
they cannot be taxed with desertion. Probably they felt little interest
in the event of the struggle. Habit and circumstance caused them to send
their contingent to Arbela at the call of the Great King; but when the
Persian cause was evidently lost, they felt it needless to make further
sacrifices. Having no hope of establishing their independence, they
thought it unnecessary to prolong the contest. They might not gain, but
they could scarcely lose, by a change of masters.

CHAPTER III.

_Condition of Western Asia under the earlier