in full Lucius Septimius Severus Pertinax
born AD 145, Leptis Magna, Tripolitania
died Feb. 4, 211, Eboracum, Britain
Roman emperor (193–211).
He was in Europe in command of Rome's largest army when the emperor Publius Helvius Pertinax was murdered. Named emperor by his troops, he marched on Rome, entering the city without resistance. He effectively made Rome a military monarchy, giving the army a dominant role in government, ignoring the Senate , choosing officials from among the equites (see eques ) and granting control of the courts to the Praetorian prefect . He annexed Mesopotamia, and he died attempting to subdue non-Roman Britain. He named his son Caracalla his successor.