[4] These political differences saw the two consuls almost immediately begin quarrelling in 87 BC over policy, in which Cinna wanted to enrol the new citizens (Italian allies) across all of the Roman tribes.
Because of his interest in soothsayers, modern scholars have supposed that Octavius was a member of the decemviri sacris faciundis, the priests in charge of the Sibylline books.
Cinna and his supporters began using violence to intimidate the tribunes to withdraw their veto, leading to a full-scale riot in the Roman Forum.
Pompeius Strabo was initially unwilling to cooperate with Octavius, but eventually moved his troops to the vicinity of Rome, just outside the Colline Gate.
[14] Fearful of this turn of events, and of news that the Senate was also contemplating coming to terms with Cinna, he fell out with Metellus Pius, who had initially refused his soldiers' demands that he take command from Octavius.
[16] Although Cinna gave a vague promise that no harm would come to Octavius, Octavius was persuaded by a group of colleagues to abandon the forum and set himself up on the Janiculum as consul in protest against the recognition of Cinna, accompanied by a small number of nobles and a tiny remnant of his military forces.
Plutarch, who discusses him in his lives of Marius and Lucius Cornelius Sulla, describes Gnaeus Octavius's character as "reputable".