Gnaeus Pompeius Magnus, more famous as Pompey the Great.
The letter cited here was sent from Marcus Caelius Rufus to Cicero and it discusses the, back then, recent events and the imminent risk of civil war.
"I have often told you in my letters that I see no chance of peace lasting a year; and the nearer the struggle comes, which must come, the clearer does that danger appear. The point, on which the men in power are bound to fight, is this - Cn. Pompeius has made up his mind not to allow C. Caesar to become consul, except on condition of his first handing over his army and provinces: while Caesar is fully persuaded that he cannot be safe if he quits his army."
Cicero - Letters CCLXXIX
Translated by E. S. Shuckburgh 1908-1909