Political map of Europe & the Mediterranean 19 April 193 (Year of the Five Emperors): Commodus’ successor Pertinax reigned for only three months before being assassinated by the Praetorian Guard, who objected to his curtailing of their authority. The Guard sold the position of Emperor to Didius Julianus, but his rule was quickly challenged by Pescennius Niger in Syria, Septimius Severus in Pannonia, and Clodius Albinus in Britain.