GALLIE'NUS, PUBLICS LICINIUS, eon of the Emperor Vale rianus, was made Caner and colleague to his father A.D. 253. In a great battle near Milan ho defeated the Alemanni and other northern tribes which had made an irruption into North Italy, and gave evidence of his personal bravery and abilities. Ile was also well informed in literature, and was both an orator and a poet. When Valerianus was taken prisoner by the Persians, in 260, Gallienus took the reins of government, and was acknowledged as Augustus. Ito appears to have given himself up to debauchery and the company of profligate persons, neglecting the interests of the empire, and taking no steps to effect the release of his father from his hard captivity, in whioh be died. The barbarians attacked the empire on every aide ; revolts broke out in various provinces, where several commanders assumed the title of emperor, whilst Gallienus was loitering at Rome with his favourites and mistresses. Yet now and then ha seemed to awaken from his torpor at the news of the advance of the invaders, and, putting himself at the head of the legions, he defeated Ingenue, who had usurped the imperial title in Illyricum. But he disgraced his
victory by horrible cruelties. Meantime Probua, Aurelianua, and other able commanders, were strenuously supporting the honour of the Roman arms in the east, where Odenatus, prince of Palmyra, acted as a useful ally of the Romans against the Persians. Usurpers arose in Egypt, in the Gauls, in Thrace, in almost every province of the empire, from which circumstance this period has been styled the reign of the thirty tyrants.' At last Aureolus, a man of obscure birth (some say a Dacian shepherd originally), but a brave soldier, was proclaimed emperor by the troops in Illyricum, entered Italy, took possession of Milan, and even marched against Rome while Gallienus was absent. Gallienus returned quickly, repulsed Aureolua, and defeated him in a great battle near the Adda, after which the usurper abut himself up in Milan, where he was besieged by Gallienus ; but during the siege the emperor was murdered by some conspirators, in 263. He was succeeded by Claudius II. Trebelliva Pollio has written a history of the reign of Gallienus. See also Zeuaras, Aurelius Victor, and Eutropius.