Antoninus Pius died in 161, and Marcus assumed the imperial state. He at once associated with himself L. Ceionius Commodus, whom Antoninus had adopted as a younger son at the same time with Marcus, giving him the name of Lucius Aurelius Verus. Henceforth the two are colleagues in the empire, the junior being trained as it were to succeed. No sooner was Marcus settled upon the throne than wars broke out on all sides. In the east, Vologeses III. of Parthia began a long-meditated revolt by destroying a whole Roman Legion and invading Syria (162). Verus was sent off in hot haste to quell this rising; and he fulfilled his trust by plunging into drunkenness and debauchery, while the war was left to his officers. Soon after Marcus had to face a more serious danger at home in the coalition of several powerful tribes on the northern frontier. Chief among those were the Marcomanni or Marchmen, the Quadi (mentioned in this book), the Sarmatians, the Catti, the Jazyges. In Rome itself there was pestilence and starvation, the one brought from the east by Verus's legions, the other caused by floods which had destroyed vast quantities of grain. After all had been done possible to allay famine and to supply pressing needs--Marcus being forced even to sell the imperial jewels to find money--both emperors set forth to a struggle which was to continue more or less during the rest of Marcus's reign. During these wars, in 169, Verus died. We have no means of following the campaigns in detail; but thus much is certain, that in the end the Romans succeeded in crushing the barbarian tribes, and effecting a settlement which made the empire more secure. Marcus was himself commander-in-chief, and victory was due no less to his own ability than to his wisdom in choice of lieutenants, shown conspicuously in the case of Pertinax. There were several important battles fought in these campaigns; and one of them has become celebrated for the legend of the Thundering Legion. In a battle against the Quadi in 174, the day seemed to be going in favour of the foe, when on a sudden arose a great storm of thunder and rain the lightning struck the barbarians with terror, and they turned to rout. In later days this storm was said to have been sent in answer to the prayers of a legion which contained many Christians, and the name Thundering Legion should be given to it on this account. The title of Thundering Legion is known at an earlier date, so this part of the story at least cannot be true; but the aid of the storm is acknowledged by one of the scenes carved on Antonine's Column at Rome, which commemorates these wars.