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 far as the river Cyrus.

On the Cyrus, however, he was met by Aspacures, the king of Sapor's choice, who made proposals for an accommodation.

Representing himself as really well-inclined to Rome, and only prevented from declaring himself by the fact that Sapor held his son as a hostage, he asked Terentius' consent to a division of Iberia between himself and his rival, the tract north of the Cyrus being assigned to the Roman claimant, and that south of the river remaining under his own government.

Terentius, to escape further trouble, consented to the arrangement; and the double kingdom was established.
The northern and western portions of Iberia were made over to Sauromaces; the southern and eastern continued to be ruled by Aspacures.
When the Persian king received intelligence of these transactions he was greatly excited.