" Knowing the sloth of the Emperor Julianus, Severus, who was leader of the army in Slavonia, persuaded the troops that it would be well to go to Rome ‘(Q avenge the death of Pertinax, who had been slain by the Praetorian guard, and under this pretext, without revealing his aspirations to the throne, marched with his army to Rome and was in Italy before his departure was known."

Chapter 19 That We Must Avoid Being Despised and Hated, line 45.