It must have been with a heavy heart that he set out once more for Germany to face the dangerous rising of the Quadi and Marcomanni. To obtain soldiers sufficient to fill up the vacancies in his army which had been decimated by the plague, he was forced to enrol slaves; and to obtain money he had to sell the ornaments of the palace, and even some of the Empress's jewels. Immediately before he started his heart was wrung by the death of his little boy, the twin-brother of Commodus, whose beautiful features are still preserved for us on coins. Early in the war, as he was trying the depth of a ford, he was assailed by the enemy with a sudden storm of missiles, and was only saved from imminent death by being sheltered beneath the shields of his soldiers. One battle was fought on the ice of the wintry Danube. But by far the most celebrated event of the war took place in a great victory over the Quadi which he won in A.D. 174, and which was attributed by the Christians to what is known as the "Miracle of the Thundering Legion." Divested of all extraneous additions, the fact which occurred,--as established by the evidence of medals, and by one of the bass-relievi on the "Column of Antonine,"--appears to have been as follows. Marcus Aurelius and his army had been entangled in a mountain defile, into which they had too hastily pursued a sham retreat of the barbarian archers. In this defile, unable either to fight or to fly, pent in by the enemy, burned up with the scorching heat and tormented by thirst, they lost all hope, burst into wailing and groans, and yielded to a despair from which not even the strenuous efforts of Marcus could arouse them. At the most critical moment of their danger and misery the clouds began to gather, and heavy shows of rain descended, which the soldiers caught in their shields and helmets to quench their own thirst and that of their horses. While they were thus engaged the enemy attacked them; but the rain was mingled with hail, and fell with blinding fury in the faces of the barbarians. The storm was also accompanied with thunder and lightning, which seems to have damaged the enemy, and filled them with terror, while no casualty occured in the Roman ranks. The Romans accordingly regarded this as a Divine interposition, and achieved a most decisive victory, which proved to be the practical conclusion of a hazardous and important war. The Christians regarded the event not as _providential but as miraculous_, and attributed it to the prayers of their brethren in a legion which, from this circumstance, received the name of the "Thundering Legion." It is however now known that one of the legions, distinguished by a flash of lightning which was represented on their shields, had been known by this name since the time of Augustus; and the Pagans themselves attributed the assistance which they had received sometimes to a prayer of the pious Emperor and sometimes to the incantations of an Egyptian sorcerer named Arnuphis.