Septimius Severus (//; Latin: Lucius Septimius Severus Augustus; 11 April 145 – 4 February 211), also known as Severus, was Roman emperor from 193 to 211. He was born in Leptis Magna in the Roman province of Africa. As a young man he advanced through the cursus honorum—the customary succession of offices—under the reigns of Marcus Aurelius and Commodus. Severus seized power after the death of Emperor Pertinax in 193 during the Year of the Five Emperors.
After deposing and killing the incumbent emperor Didius Julianus, Severus fought his rival claimants, the Roman generals Pescennius Niger and Clodius Albinus. Niger was defeated in 194 at the Battle of Issus in Cilicia. Later that year Severus waged a short punitive campaign beyond the eastern frontier, annexing the Kingdom of Osroene as a new province. Severus defeated Albinus three years later at the Battle of Lugdunum in Gaul.
After consolidating his rule over the western provinces, Severus waged another brief, more successful war in the east against the Parthian Empire, sacking their capital Ctesiphon in 197 and expanding the eastern frontier to the Tigris. He then enlarged and fortified the Limes Arabicus in Arabia Petraea. In 202 he campaigned in Africa and Mauretania against the Garamantes; capturing their capital Garama and expanding the Limes Tripolitanus along the southern desert frontier of the empire. He proclaimed as Augusti (co-emperors) his elder son Caracalla in 198 and his younger son Geta in 209.
In 208 he travelled to Britain, strengthening Hadrian's Wall and reoccupying the Antonine Wall. In the same year he invaded Caledonia (modern Scotland), but his ambitions were cut short when he fell fatally ill in late 210. Severus died in early 211 at Eboracum (today York, England), and was succeeded by his sons, thus founding the Severan dynasty. It was the last dynasty of the Roman empire before the Crisis of the Third Century.
Born on 11 April 145 at Leptis Magna (in present-day Libya) as the son of Publius Septimius Geta and Fulvia Pia, Septimius Severus came from a wealthy and distinguished family of equestrian rank. He had Italian Roman ancestry on his mother's side and descended from Punic – and perhaps also Libyan – forebears on his father's side.
Severus' father, an obscure provincial, held no major political status, but he had two cousins, Publius Septimius Aper and Gaius Septimius Severus, who served as consuls under the emperor Antoninus Pius r. 138–161. His mother's ancestors had moved from Italy to North Africa; they belonged to the gens Fulvia, an Italian patrician family that originated in Tusculum. Septimius Severus had two siblings: an older brother, Publius Septimius Geta; and a younger sister, Septimia Octavilla. Severus's maternal cousin was the praetorian prefect and consul Gaius Fulvius Plautianus.