The Parthian War (161-166)
Marcus Aurelius Distributing Bread to the People 1765 Oil on canvas, 300 x 301 cm Musée de Picardie, Amiens
The incursion in northern Britain and the difficulties along the Danube were soon satisfactorily managed by legates. The danger in the East was of a different magnitude. Tensions between Rome and Parthia had intensified in the last years of Antoninus' reign over control of Armenia, the vast buffer state which had often aroused enmity between the two powers, since each wished to be able to impose a king favorable to its interests. With Antoninus' death and the uncertainty attendant upon a new emperor (in this case two, a dyarchy, for the first time in Rome's history), the Parthian monarch, Vologaeses III, struck rapidly, placed his own candidate upon the Armenian throne, and inflicted severe setbacks upon the Roman forces sent to oppose him. Marcus decided to send his colleague Lucius Verus, whose imperial prestige would underscore the seriousness of the empire's response.
Verus lacked military experience and was sorely lacking in the attributes of leadership and command; further, he was notorious for being chiefly interested in amusements and luxury. But Marcus surrounded him with several of the best generals at the empire's disposal, chief among them Avidius Cassius (c.130-175)(PIR2 A1402). From 162 on, Rome's successes and conquests were extensive and decisive. Most of Parthia's significant cities and strongholds, such as Seleucia and Ctesiphon, were stormed and destroyed, and the army's movements eastward recalled the movements of Alexander the Great some five centuries earlier. By 166, Parthia had capitulated and a Roman nominee sat on the Armenian throne. The victory appeared to be the most decisive since Trajan's conquest of Dacia, but, when Verus returned to Italy with his triumphant army, there came also a devastating plague, which had enormous effect on all provinces.
As is the case with all ancient diseases, it is almost impossible to identify this one. In all likelihood, however, it was smallpox; how severe the toll was is debated.[[10]] Clearly, it cast a pall over the triumph celebrated by the two emperors, who were honored with the titles Armeniacus and Parthicus. The last years of this decade were dominated by efforts to overcome the plague and provide succour to its victims. But already in 166, the German tribes smashed the Danubian limes, threatening the empire's stability and even existence,more than Parthia had ever done. From the north had come a far greater threat to the empire's stability, indeed existence, than that of Parthia had been. The first campaigns were punctuated by the death of Verus in 169, leaving Marcus as sole emperor. And so began the most difficult period of his life.
The German Wars
Early in 169, the Marcomanni and Quadi crossed the Danube, penetrated the intervening provinces, and entered Italy. The culmination of their onslaught was a siege of Aquileia. The effect upon the inhabitants of the peninsula was frightful. This was the first invasion of Italy since the late second century B.C., when the Cimbri and Teutones had been separately crushed by Marius. Perhaps more vivid in the collective imagination was the sack of Rome by the Gauls in 387, when the city was saved only by the payment of ransom.
The two emperors hastened north, after a rapid mobilization of forces, which included the drafting of slaves, since the manpower potential of the empire had been so impaired by the consequences of the plague and the losses and troop commitments in the East. Verus died while in the north;[[11]] Marcus returned to Rome with the body and gave his brother full honors. He then turned north again and began his counterattacks against the barbarians. He did not know it at the time, but he was destined to spend most of his remaining years on the northern frontier. The only interlude was caused by revolt in the east.
We have no record of Marcus' ultimate intentions in these campaigns, yet the various stages were clear. First and foremost, the enemy had to be driven out of Italy and then into their own territory beyond the Danube. He strove to isolate the tribes and then defeat them individually, so that the ultimate manpower superiority of the empire and its greater skill in warfare and logistics could more easily be brought to bear. It was a successful strategy, as one tribe after another suffered defeat and reestablished ties with Rome. But it was a time-consuming and expensive operation, requiring the recruitment of two new legions, II Italica and III Italica, the construction of many new camps, such as the legionary fortress at Regensburg, with success accruing year by year. He intended to create two new provinces, Marcomannia and Sarmatia, thereby eliminating the Hungarian Plain and the headwaters of the Elbe as staging areas for invasion.
This steady, slow progress was interrupted in 175 by the action of the distinguished general Avidius Cassius, governor of Syria, who claimed the empire for himself. Whether he responded to a rumor of Marcus' death or, as gossip had it, conspired with Marcus' wife, the emperor's response was quick and decisive. Leaving the northern wars, he traveled to the East, but Avidius was killed before Marcus arrived in the region. After spending time settling affairs and showing himself to some of the provinces, with particular attention shown to Athens, where he was initiated into the Eleusinian mysteries, as Hadrian and Verus had been. He returned to Italy and soon answered the call to duty once more on the northern frontier. He took with him as colleague his son Commodus, now merely sixteen years old but already long since marked out as his father's intended successor. The military campaigns proved successful, but in the spring of 180, when Marcus died, at least one more year of warfare was necessary for the attainment of the grand enterprise. Marcus recommended to Commodus continuation of the war, but the new emperor was eager to return to Rome and the ease and luxury of the imperial court and entered into a peace agreement. Never again was Rome to hold the upper hand in its dealings with the Germanic tribes beyond the now reestablished borders of the empire.