[1][4] Previously his father had been tried before the people by the tribune Gaius Norbanus for his catastrophic loss at the Battle of Arausio; he was convicted and banished.
[1] Caepio was later brought to trial around 95 BC on maiestas charges from actions as quaestor, but – defended by Lucius Licinius Crassus – he was acquitted.
[1] In 92 BC, Caepio prosecuted Marcus Aemilius Scaurus, the eminent princeps senatus, for alleged provincial extortion and taking bribes from Mithridates VI of Pontus.
[5] Scaurus was apparently driven by the experience of the affair to side with Caepio's former brother-in-law, Livius Drusus, who was to be tribune in 91 BC.
Broughton assigns a supposed praetorship to Caepio in (possibly) 91,[6] but Sumner disputes this, saying there's no evidence that he held the office.
[7] Caepio became a chief opponent of Marcus Livius Drusus' legislative programme for 91,[1] which included laws aimed at giving full citizenship to the Italians and reform the jury pool for various criminal trials.
Caepio, it was rumoured, was even involved in the assassination of Drusus, an event commonly seen by ancient sources as starting the Social War.
[8][dubious – discuss] Early in 90 BC, Caepio initiated a suit with Quintus Varius Severus against Marcus Aemilius Scaurus for a second time but left to serve as legate in the Social War.
[9][10] During the Social War, Caepio served as a legate under the consul Publius Rutilius Lupus fighting the northern group of rebels.
As further confirmation of his good faith he brought masses of gold and silver (which were actually lead, plated with precious metal).