Valerian (193/195/200-260/264) was from a traditional senatorial family; and served under various emperors. When Emperor Trebonianus Gallus faced rebellion from rival claimant Aemilianus in 253; he turned to Valerian for aid. Valerian was too late to save Gallus; who was murdered by his own troops; but his arrival saw Aemilianus' legions kill their own emperor and defect to Valerian's side; declaring him the new emperor in late 253.

He inherited a Roman Empire that was going through tumultuous times. The West fell into disorder; while various portions of the East were being subsumed into the Sassanid Empire. Making his son Gallienus co-emperor; they divided responsibilities between themselves; Gallienus taking the West while Valerian headed East to fight the Sassanids. While he was fighting the Sassanids; Valerian also continued the persecution of Christians started by previous emperors; demanding them perform sacrifices to Roman gods or face banishment and execution.

In 260; after being decisively defeated in the Battle of Edessa; Valerian arranged for a peace settlement with Shapur I; ruler of the Sassanid Empire. Shapur betrayed the truce however; and captured Valerian; holding him prisoner for the rest of the emperor's life. He would die in captivity; with accounts of his death ranging from being flayed alive to being forced to swallow molten gold.