Cylaces and Artabannes commenced the siege of Artogerassa, and for a time pressed it with vigor, while they strongly urged the garrison to make their submission.  But, having entered within the walls to negotiate, they were won over by the opposite side, and joined in planning a treacherous attack on the besieging force, which was surprised at night and compelled to retire.  Para took advantage of their retreat to quit the town and throw himself on the protection of Valens, the Roman emperor, who permitted him to reside in regal state at Neocaesarea.  Shortly afterwards, however, by the advice of Cylaces and Artabannes, he returned into Armenia, and was accepted by the patriotic party as their king, Rome secretly countenancing his proceedings.  Under these circumstances the Persian monarch once more took the field, and, entering Armenia at the head of a large army, drove Para, with his counsellors Cylaces and Artabannes, to the mountains, renewed the siege of Artogerassa, and forced it to submit, captured the queen Pharandzem, together with the treasure of Arsaces, and finally induced Para to come to terms, and to send him the heads of the two arch-traitors.  The resistance of Armenia would probably now have ceased, had Rome been content to see her old enemy so aggrandized, or felt her hands absolutely tied by the terms of the treaty of Dura.

But the success of Sapor thus far only brought him into greater difficulties.  The Armenians and Iberians, who desired above all things liberty and independence, were always especially hostile to the power from which they felt that they had for the time being most to fear.  As Christian nations, they had also at this period an additional ground of sympathy with Rome, and of aversion from the Persians, who were at once heathens and intolerant.  The patriotic party in both countries was thus violently opposed to the establishment of Sapor’s authority over them, and cared little for the artifices by which he sought to make it appear that they still enjoyed freedom and autonomy.  Above all, Rome, being ruled by monarchs who had had no hand in making the disgraceful peace of A.D. 363, and who had no strong feeling of honor or religious obligation in the matter of treaties with barbarians, was preparing herself to fly in the face of her engagements, and, regarding her own interest as her highest law, to interfere effectually in order to check the progress of Persia in North-Western Asia.

Rome’s first open interference was in Ibera.  Iberia had perhaps not been expressly named in the treaty, and support might consequently be given to the expelled Sauromaces without any clear infraction of its conditions.  The duke Terentius was ordered, therefore, towards the close of A.D. 370, to enter Iberia with twelve legions and replace upon his throne the old Roman feudatory.  Accordingly he invaded the country from Lazica, which bordered it upon the north, and found no difficulty in conquering it as