Septimius, however, proceeded more cautiously. Having assumed Albinus, who commanded in Britain, as his partner, and secured the strong-holds in Ger many, he marched to Rome at the head of his army. At the urgent request of Didius, the senate proclaim ed him a traitor; but all the attempts of Didius were unable to organize an effective force, and, perplexed with opposite counsels, he waited the approach of his rival. When Severus had advanced near to Rome, Didius, with the consent of the senate, sent ambassa dors to offer him a share in the concern; but when the general rejected this offer, the senate immediately as sembled, and having passed a decree depriving Didius of the empire, they proclaimed Severus in his place. Didius was ordered by the senate to be slain, and, when the executioners had performed their office, after great remonstrances and wailing on the part of Di dius, they stuck up his head in the court of justice, where he had formerly carried on his professional pur suits.
Severus was now declared emperor by the senate in the 47th year of his age. Before he entered Rome, he ordered the Prretorian soldiers, who had sold the empire, to come out unarmed to meet him. Flaying no alternative but compliance, they marched out with laurels in their hands to welcome his approach; but Severus, after reproaching them for their crimes, ordered then, to be stripped of their military equip ments, deprived of the title and rank of soldiers, and banished to the distance of 100 miles from Rome. Severus then made his entrance into the city. The streets were strewed with flowers, and the senate re ceived him with open arms, and granted him every ho nour and title that he desired, while he in return pro mised to govern with justice and moderation. In or der to secure adherents, he seized all the children of those who occupied situations of authority in the east, and he kept them as hostages for the good conduct of their fathers. He next supplied the city with corn, and hastened to Syria to attack Niger, who still reigned in the east under the title of Augustus. After many obstinate engagements between the rival sovereigns, a decisive battle took place on the plains of the Issus, in which Niger was totally defeated with the loss of 20,000 men. The head of Niger was cut off, and car ried on the point of a lance to Severus, who exercised the greatest severity against the adherents of his ri val. The Parthians, and several of the neighbouring nations, had taken up arms in defence of Niger; but Severus defeated them in such decisive battles that he put down all his enemies in the east.
Having thus established peace, and even enlarged the empire, Severus resolved to get rid of Claudius Albinus, whom he had assumed as' his partner in the empire at a time when he dreaded his influence and power. Under the guise of messengers carrying des patches, he sent assassins into Britain to murder Al binus ; but the general, being informed of their de signs, assumed a warlike attitude, and proclaimed himself emperor. These rival leaders met each other
in Gaul, where they carried on a vigorous, though an indecisive campaign.
A desperate engagement at last took place, which continued from morning till night with variable though equal success. The troops of Severus at last gave way; and he himself falling from his horse, the rival army raised the shouts of victory. A body of reserve, however, under Lwtus, one of Severus's officers, who intended to destroy both parties and assume the sove reignty, restored the fury of the battle, and enabled Severus to rally his troops, and make a desperate charge against Albinus. This attack was made with such skill and bravery, that the army of Albinus was pursued into the city of Lyons, and he himself taken prisoner and slain. In place of using this victory with moderation, Severus executed all the senators who were taken prisoners; and he treated with unmanly in solence the bodies of those who fell.
In order to establish himself in the power which he had now acquired, he distributed rewards and ho nours in the most profuse manner among his troops, and having given the charge of the government to one Plautianus, whose daughter his son Caracalla had married, Severus, accompanied by his sons Caracalla and Geta, undertook an expedition against the Par thians, who had then assumed an hostile attitude on his eastern frontier. In this campaign he subjugated Armenia, and making himself master of Seleucia, Babylon, and Ctesiphon, he subdued the kingdom of Parthia. From Parthia he advanced to the south of Asia, and, after visiting the tomb of Pompey the Great, and granting a senate to Alexandria, he stu died with an inquiring eye the various monuments and ruins which even at that time rendered Egypt an object of general interest.
During the absence of Severus and his sons, Plauti anus conceived the design of seizing the empire ; and no sooner had Severus returned, than Plautianus en gaged a tribune of the Praetorian bands, whom he commanded to assassinate both Severus and Caracal la. The tribune lost no time in communicating the intelligence to Severus, who treated it as a plot de vised by the enemies of his favourite. The tribune at last requested permission to bring Plautianus to the emperor's apartment, and having informed him that he had slain both Severus and Caracalla, Plautianus was ordered to follow him to the palace. Conducted at midnight to the place of murder, he found Severus encircled by his friends, and ready to receive him. Confounded at the sight, he confessed his designs. The emperor was disposed to pardon him; but Cara calla, heedless of the supplications of the criminal, ran him through the body with his sword.