the greater part of his acquisitions.  Thus the threatened conquest proved a mere inroad, and instead of a power of greater strength replacing Syria in these regions, Syria practically retained her hold of them, but with enfeebled grasp, her strength crippled, her prestige lost, and her honor tarnished.  Ptolemy had, it is probable, not retired very long, when, encouraged by what he had seen of Syria’s weakness, Tiridates took the aggressive, and invading the neighboring district of Hyrcania, succeeded in detaching it from the Syrian state, and adding it to his own territory.  This was throwing out a challenge which the Syrian monarch, Callinicus, could scarcely decline to meet, unless he was prepared to lose, one by one, all the outlying provinces of his empire.

Accordingly in B.C. 237, having patched up a peace with his brother, Antiochus Hierax, the Syrian monarch made an expedition against Parthia.  Not feeling, however, altogether confident of success if he trusted wholly to his own unaided efforts, he prudently entered into an alliance with Diodotus the Bactrian king, and the two agreed to combine their forces against Tiridates.  Hereupon that monarch, impressed with a deep sense of the impending danger, quitted Parthia, and, proceeding northwards, took refuge with the Aspasiacae, a Scythian tribe which dwelt between the Oxus and the Jaxartes.  The Aspasiacae probably lent him troops; at any rate, he did not remain long in retirement, but, hearing that the Bactrian king, whom he especially feared, was dead, he contrived to detach his son and successor from the Syrian alliance, and to draw him over to his own side.  Having made this important stroke, he met Callinicus in battle, and completely defeated his army.

This victory was with reason regarded by the Parthians as a sort of second beginning of their independence.  Hitherto their kingdom had existed precariously, and as it were by sufferance.  It could not but be that the power from which they had revolted would one day seek to reclaim its lost territory; and, until the new monarchy had measured its strength against that of its former mistress, none could feel secure that it would be able to maintain its existence.  The victory gained by Tiridates over Callinicus put an end to these doubts.  It proved to the world at large, and also to the Parthians themselves, that they had nothing to fear—­that they were strong enough to preserve their freedom.  Considering the enormous disproportion between the military strength and resources of the narrow Parthian State and the vast Syrian Empire—­considering that the one comprised about fifty thousand and the other above a million of square miles; that the one had inherited the wealth of ages and the other was probably as poor as any province in Asia; that the one possessed the Macedonian arms, training, and tactics, while the other knew only the rude warfare of the Steppes—­the result of the struggle cannot but be regarded as surprising.