The Prince by Niccolo Machiavelli Chapter 19 Page 16

the fox, each of which natures, as I have observed before, a Prince should know how to assume.

Knowing the indolent disposition of the Emperor Julianus, Severus persuaded the army which he commanded in Illyria that it was their duty to go to Rome to avenge the death of Pertinax, who had been slain by the Pretorian guards. Under this pretext, and without disclosing his design on the Empire, he put his army in march, and reached Italy before it was known that he had set out. On his arrival in Rome, the Senate, through fear, elected him Emperor and put Julianus to death. After taking this first step, two obstacles still remained to his becoming sole master of the Empire; one in Asia, where Niger who commanded the armies of the East had caused himself to be proclaimed Emperor; the other in the West, where Albinus, who also aspired to the Empire, was in command.