Septimius Severus (193 - 4 February 211CE). Lucius Septimius Severus was an outstanding military leader who seized power after the death of Pertinax in the Year of the Five Emperors (193). He deposed and killed Emperor Didius Julianus, and defeated his other rivals Pescennius Niger and Clodius Albinus. He began the conquest of Caledonia (Scotland) in 208, but died of illness before completion. He was the founder of the Severan Dynasty, the last dynasty before the Crisis of the Third Century.