The Scythians, whom he had called to his aid under the pressure of the Syrian invasion, and who had arrived too late to take part in the war, demanded the pay which they had been promised, and suggested that their arms should be employed against some other enemy.

Phraates was unwilling either to requite services not rendered, or to rush needlessly into a fresh war merely to gratify the avarice of his auxiliaries.

He therefore peremptorily refused to comply with either suggestion.

Upon this, the Scythians determined to take their payment into their own hands, and began to ravage Parthia and to carry off a rich booty.

Phraates, who had removed the headquarters of his government to Babylonia, felt it necessary to entrust affairs there to an officer, and to take the field in person against this new enemy, which was certainly not less formidable than the Syrians.