408 ROME who restored the Euphrates as the eastern boundary of the empire. Hadrian was suc- ceeded by Antoninus Pius, whose heir was Marcus Aurelius Antoninus (161-'80). The 84 years of the reigns of Nerva, Trajan, Hadrian, and the two Antonines are considered the hap- piest period of the Roman empire ; and from the year of the accession of Commodus, son of Marcus Aurelius, A. D. 180, Gibbon dates the commencement of that empire's decline. At that time the empire consisted of Italy, Spain, Gaul, Britain, Rhsetia, Noricum and Pannonra, Dalmatia, Moesia and Dacia, Thrace, Macedonia, and Greece; Asia Minor, Syria, Phoenicia, and Palestine; Egypt and all the north of Africa, and the Mediterranean with its islands. The population is estimated at 120,000,000. The emperor Commodus became one of the worst of the imperial tyrants, and was assassinated (192). His successor, Perti- nax, was murdered by the prrotorians, who sold the empire to Didius Julianus, to whom succeeded Septimius Severus (193). Severus's son Caracalla, and the successor of the latter, Elagabalus, rivalled Caligula and Nero in in- famy. Most of the emperors who subsequent- ly reigned were men of little ability down to Diocletian, including Maximin, the three Gor- dians, Philip, Balbinus, Valerian, Gallienus, Claudius II., Tacitus, Probus, Cams, Carinus, Numerian, and others, and their conduct accel- erated the decline of the empire. Alexander Severus (222-'35), Decius, and Aurelian are the principal exceptions, the last named con- quering Zenobia and destroying Palmyra (273). Under the rule of Diocletian (284-305) the empire was so strengthened that its power enjoyed a certain revival ; but its constitution was essentially changed by that sovereign. The principles of a despotism yet unknown were adopted and carried into effect by him, togeth- er with the usages and pomps of oriental courts, totally foreign to the ancient simplicity with which all but the more lascivious and vicious emperors had contented themselves. Diocle- tian associated with himself a colleague on the throne, Maximianus; and subsequently two others with the subordinate rank of Cresar, each of the supreme rulers being henceforth styled Augustus. Rome then ceased to be the seat of government, Diocletian residing prin- cipally at Nicomedia in Bithynia, and Maximi- anus at Milan. The senate sunk into total insignificance, and from this period the empe- rors rarely appeared in the ancient capital, except on occasions of grand festivals or tri- umphs. Constantino the Great, the son of Constantius Chlorus, the first of the Christian emperors, after the death of the associate or rival rulers Maxentius, Galerius, Maximinus, and Licinius, formally transferred the capital to Byzantium, thenceforth called Constantino- ple, though its founder meant that it should be called New Rome. From that time, A. D. 330, should be dated the cessation of the Ro- man ascendancy, though the remains of the empire continued to influence the world down to the middle of the 15th century, when Con- stantinople fell into the hands of the Turks. The Roman element was little known in the empire after the abandonment of the city on the Tiber, and that abandonment was the con- sequence of the change that had come over the world since the fall of the republic. Con- stantine only did that which other rulers had contemplated, in transferring the seat of em- E're permanently to some other place than ome, that transference simply rounding and completing the imperial policy which had been inaugurated by the first of the Caesars. He divided the empire on his death between his three sons. Constantino II. inherited Gaul, and attempted to seize Italy, which had fallen to the share of his youngest brother Constans, but was slain in the attempt, and Constans, master now of both Italy and Gaul, was subse- quently assassinated by his general Magnentius. The whole empire finally came into the posses- sion of the second brother, Constantius (351), who on his father's death had been assigned the provinces of the East. The northern bar- barians, having penetrated into northern and eastern Gaul, were driven out by Julian, who succeeded to the purple in 361, restored pagan- ism, and fell in 863 in an expedition into Per- sia. Paganism fell with him. The army con- ferred the crown upon Jovian, who bought a disgraceful peace and died before he reached Constantinople, leaving the selection of an em- peror again to the soldiers. The choice fell upon Valentinian I., who appointed his brother Valens his colleague, and left to him the gov- ernment of the East, with a part of Illyricum. The weak and unfortunate reign of Valens (364-378) was signalized by the overthrow of the Goths by the Huns, and the establishment of the defeated tribe within the limits of the empire. Revolting in consequence of their ill treatment by the Romans, they were attacked by Valens in person, defeated him at Adrian- ople, and forced him to take refuge in a hut, where he perished by fire. More than 60,000 Roman soldiers fell in this battle, and the Goths ravaged the whole country from the scene of the conflict to the walls of Constanti- nople. In this moment of danger the hopes of the East were turned on the court of Treves, where Gratian, the son of Valentinian I., ruled over the western division of the empire, while his younger brother, Valentinian II., governed Italy and Africa. Gratian chose as his col- league Theodosius, and caused him to be pro- claimed emperor of the East (379). He him- self, after a not inglorious reign (367-'83), was assassinated in a military insurrection, and suc- ceeded by Maximus, who soon turned his arras against Valentinian II. and drove him out of Italy. Theodosius in the mean time had re- stored peace to the East, and was now enabled to attack the usurper, defeated him on the banks of the Save (388), and caused him to be put to death. Valentinian perished soon after by
