As the Roman arms were carried still farther to the eastward, and all the countries reduced, to the confines of Persia, the plague seems to have become more common among them. In the time of Marcus Aurelius, a war was undertaken against the Parthians, which was carried on by the Romans with great success, and with no less cruelty; for, though the city of Seleucia opened its gates to the Roman general, he caused the inhabitants, to the number of four hundred thousand, to be massacred. But they soon paid dear for this cruelty, by a dreadful pestilence, which broke out, according to the historian Ammianus Marcellinus, in the very city which they had desolated, and was brought by their army into Italy, from whence it spread throughout the whole empire. Other historians say, that it originated in Ethiopia, from whence it spread into Egypt, and thence into the country of the Parthians. We know not how long the infection continued; only that, some years afterwards, when the emperor was defeated by the Germans, the pestilence still raged to such a degree, that slaves, gladiators, and even the banditti of Dalmatia and Dardania, were enlisted for the defence of the empire. It is certain that great havock must have been made by it, as we find that the barbarians were encouraged to invade the empire on all sides, and could scarcely be repulsed; insomuch that historians compare this with the most destructive wars the Romans had ever waged.[18] [18] Univ. Hist. vol. xv. During the time that the empire was overrun by the northern barbarians, the plague frequently made its appearance; which we shall have occasion to notice more particularly in the following section; but in those times the destruction by the sword was so extraordinary, that less mention is made by history of any pestilential disorder. In the time of Justinian, however, about sixty-five years after the final destruction of the western empire, the most violent plague recorded in history took place. Of this we have a particular account by Procopius.[19] “The distemper (says Mr. Gibbon) arose in the neighbourhood of Pelusium, on the confines of Egypt, between the Sarbonian bog and the eastern channel of the Nile. From thence, tracing, as it were, a double path, it spread to the east, over Syria, Persia, and the Indies, and penetrated to the west, along the coast of Africa, and over the continent of Europe. In the spring of the second year, Constantinople, during three or four months, was visited by this pestilence. Such was the corruption of the air, that the pestilence was not checked, nor alleviated, by any difference of seasons. The numbers that perished in this extraordinary mortality have not been recorded; only we find that, during three months, there died at Constantinople five, and at last ten thousand a day. Many cities of the east were left vacant, and, in several districts of Italy, the harvest and vintage withered on the ground.