It was, perhaps, rather fortunate accident than profound calculation that caused the sole employment against the Romans of this arm.

The foot soldiers were needed for the rough warfare of the Armenian mountains; the horse would, it was known, act with fair effect in the comparatively open and level Mesopotamia.

As the king wanted the footmen he took them, and left to his general the troops which were not required for his own operations.
The Parthian horse, like the Persian, was of two kinds, standing in strong contrast the one to the other.

The bulk of their cavalry was of the lightest and most agile description.

Fleet and active coursers, with scarcely any caparison but a headstall and a single rein, were mounted by riders clad only in a tunic and trousers, and armed with nothing but a strong bow and a quiver full of arrows.