For 10 points, name this father of Geta and Caracalla, who founded a namesake dynasty of Roman Emperors.
The Christian martyrs Felicitas and Perpetua died under the regime of this man, and his son by Julia Domna was murdered by Macrinus. He sacked Ctesiphon, revamped the Praetorian Guard, and raised substantial taxes to support the army in the wake of the reigns of Commodus, Pertinax, and Didius Julianus. This native of Leptis Magna came to power after winning battles at the Issus and Lugdunum, which saw him defeat Pescennius Niger and Clodius Albinus. His birth in modern-day Libya made him the first Emperor to be born in Africa. For 10 points, name this father of Geta and Caracalla, who founded a namesake dynasty of Roman Emperors.
The Christian martyrs Felicitas and Perpetua died under the regime of this man, and his son by Julia Domna was murdered by Macrinus.
Lucius Septimius {Severus} [or {Severus} I]