Treachery has often had a decisive impact on military operations. Great generals have founded tactical and even strategic plans upon it—and with good reason. Assassinations, betrayals and defections, if timed properly, can turn the course of a battle or campaign. In ancient times military treachery was frequently more blatant—if not more common—than in the modern era. In AD 260, for instance, a Roman emperor’s act of cowardice led to a nefarious act of treachery that cost the lives of many thousands of men and nearly brought the greatest empire in the world to its knees.
The Roman Empire struggled for centuries with barbarians before the sack of Rome and the collapse of the Western empire in 476. Its greatest military enemy over the course of its existence was not the barbarian menace, however, but Persia. Long a threat to the Greeks, the Roman Republic and the early Roman Empire, Persia became a greater threat with the rise of the Sassanid Empire after 224. From the beginning the Sassanids pressed hard against Roman domains in what are now Turkey, Iraq and Syria as they sought access to the Mediterranean.
In 256 Emperor Valerian, who had co-ruled Rome for three years with his son Gallienus, was busy fending off attacks by a barbarian tribe, the Borani, against Roman possessions along the Black Sea when the Persians launched a terrific new offensive in Syria and Mesopotamia. Led by Sassanid King Shapur I, they occupied several important settlements and threw Roman rule in the Middle East into disarray. Their attacks forced the harassed Roman emperor to turn his weary forces southeast to face the new threat.
Three years of campaigning followed. Valerian made modest progress in containing the Persian advance, but as his troops wearied and fell victim to plague, their mood became surly and mutinous. Under constant pressure, the 60-something emperor’s nerves frayed. Unable to eliminate the Persian menace, he lashed out in frustration against his own Christian subjects, ordering a number of savage persecutions.
In 260 Shapur renewed his offensive, besieging the fortress city of Edessa in what is now southeastern Turkey. Valerian moved precipitately against the Persians with a force of 70,000 men, but as the two armies came to grips, the emperor lost his nerve. Desperate to put an end to the seemingly interminable campaigning, he attempted to bribe Shapur into returning home with a lavish gift of gold. Shapur refused the overture, so Valerian sought a face-to-face meeting —a spectacularly ill-considered decision. Shapur haughtily demanded that Valerian and his staff meet with him on Persian ground, like supplicants, and the desperate Roman emperor agreed.
Protected only by a small escort, Valerian and his staff went to meet their adversaries, only to be captured by the Persians. Valerian’s army thereupon disintegrated, either of its own accord or under a Persian onslaught, with untold thousands of casualties. Stories went about that the Roman emperor had deliberately abandoned his mutinous men and sold them out to the enemy.
Valerian’s fate remains a mystery. Accounts, some of them obviously wishful thinking on the part of Christians and others who had reason to hate the emperor, had him displayed in a cage or being used as Chapur’s mounting block for his horse, before being killed and stuffed with straw or manure, his skin dyed vermilion according to Persian custom. All we know for certain is that he was carried off into captivity and never again seen outside Persia. He was the only Roman emperor ever captured by an enemy.
In the immediate aftermath of this disaster, Persian forces overran much of what remained of Roman territory in the Middle East and entered Asia Minor. And although Roman generals were able to reclaim much of this territory and reestablish their dominance over Persia by century’s end, the blow to Roman prestige inflicted by Valerian’s capture had been catastrophic. Diversion of resources to rebuild the empire in the east led to a collapse in the west, as Frankish barbarians surged over the Rhine. Gallienus, an able general, fought heroically to save the empire from complete collapse. In 268, however, while laying siege to the city of a rival Roman general near Milan, he was assassinated by some of his own generals—like his father, done in by treachery.
Over time Valerian’s capture and other events led Rome to turn inward and develop a defensive fortress mentality. This progressive sapping of the empire’s will to exist was one of the primary factors leading to its eventual collapse.
Originally published in the May 2012 issue of Military History. To subscribe, click here.