Lucius Septimius Severus, a Roman emperor, born of a family of equestrian rank near Leptis, Africa, April 11, A. D. 146, died in Eboracum (York), Britain, Feb. 4, 211. He studied law at Rome, became advocatus fisci, and afterward held many offices under Marcus Aurelius and Commodus, at Rome and in the provinces, gaining the favor of the people whom he governed, especially in Gallia Lugdunensis, by his integrity and moderation, combined with firmness. When Commodus was assassinated (192) Seve-rus was commander of the army in Pannonia and Illyria; and after the brief reign of Perti-nax and the sale of the empire by the praetorian guard to Didius Julianus, he was proclaimed emperor by his troops at Carnuntum, and marched upon Rome. No sooner had he appeared before the city (June, 193) than he was acknowledged emperor by the senate, and Julianus was deposed and killed. His first care was to disarm and banish the praetorian guard, and put to death all concerned in the murder of Pertinax. Clodius Albinus, commander of the Roman forces in Britain, and Pescennius Niger, in Syria, had each at the same time with Severus been proclaimed emperor by his army.

The former, whom he most feared, Severus associated with himself as Caesar; and against the latter, having distributed an immense largess to the troops, he marched within 30 days after his arrival at Rome, defeated his legate AEmilianus near Cyzicus, and Pescennius Niger himself near Nicaea, and again on the gulf of Issus, where Niger was slain. Byzantium held out for three years, when it was taken (196), devastated, and dismantled, Rome being thus deprived of its strongest bulwark against the Asiatic barbarians. Meanwhile Severus had crossed the Euphrates and subdued the border tribes. He next attempted to procure the assassination of Clodius Albinus, who, hearing of his intention, passed over into Gaul. Severus marched against him, and the armies, each 150,000 strong, met near Lugdunum (Lyons), Feb. 19, 197; after a terrible slaughter, during which Severus came near losing the battle and his life, Albinus was routed, and died by his own hand. Severus trampled the body under his horse's feet, ordered the head to be cut off and carried to Rome, whither he soon followed, and put to death the family of Albinus, as he had previously that of Niger, besides many senators and others.

Soon after, marching against the Parthians, he took and plundered Ctesiphon and other cities, but was less successful against the Arabs. After spending three years more in settling the affairs of Arabia, Syria, and Egypt, he returned to Rome in 202, and gave shows and distributed money with unparalleled profusion, on occasion of his son Caracalla's marriage, and the completion of the 10th year of his reign. The next few years were passed in prosperous administration at Rome, but were disturbed by the discord and profligacy of his sons Caracalla and Geta, both of whom he associated with himself as Augusti. In 208, a war breaking out in Britain, he went thither with them. Caledonia was overrun by his soldiers to the northern extremity of the island; but 50,000 of them were destroyed by the climate and the attacks of concealed foes, and Severus retired southward and began building the wall known by his name. The Caledonians nominally submitted, but again rebelled, and he was preparing for a new campaign when he died.