The choice was left to the senate, who unanimously selected Valerian (afterwards emperor).
But Valerian, well aware of the dangers and difficulties attaching to the office at such a time, declined the responsibility.
The De prelates of Valerian is concerned with secular princes, and even as late as the 14th century the title was occasionally applied to secular magistrates.
He died, probably in the year 254 (consequently under Valerian), at Tyre, where his grave was still shown in the middle ages.
Their opportunity came with the disaster which befell the Roman army under Valerian (q.v.) at Edessa, a disaster, says ' The full text, both Greek and Palmyrene, with an English translation, is given in NSI, pp. 313-340.