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.