Cinna sought better fortune for himself by joining the failed rebellions of Lepidus and Sertorius in the 70s BC, but was recalled to Rome and granted amnesty with the support of his brother-in-law, Julius Caesar.
When Sertorius's rebellion collapsed in the later 70s BC, Cinna was granted amnesty and allowed to return to Rome, by means of a motion introduced by a tribune, Plautius, and supported by his brother-in-law, Caesar.
[4] Although he did not join the conspiracy against Caesar on the Ides of March, Cinna, in the aftermath of the deed, advanced unexpectedly into the Forum – the first of all magistrates to speak about the event – and delivered a violent harangue against the late dictator.
Cinna removed his own praetor's robe as it being the gift of a tyrant, praised Caesar's killers as tyrannicides, argued that the deed was in accord with ancestral custom, and demanded public honors for the assassins.
[6] On 17 March, Cinna went to the temple of Tellus for the first Senate meeting after the assassination – now cautiously wearing his praetorian robe once again[7] – but his earlier speech had made a deep impression, and he was recognized en route by a hostile crowd, which included veterans of Caesar.
[8] As praetor, Cornelius Cinna procured the recall of the tribunes Lucius Caesetius Flavus and Gaius Epidius Marullus, whom Caesar had exiled, and, on 28 November, he refused a provincial governorship assigned to him by the consul Marc Antony.