Other factions can start the civil war you know. My first Julii campaign I figured why start it I'll provoke it. I took diplomats to both the Scipii and Brutii and talked dirty to them. At the end of the turn the Brutii attacked me starting the civil war, I got outlawed 1 turn after the Brutii did
Once 1 faction gets outlawed they all do from my observation, maybe on a rare occasion the senate will side with a weak Roman faction but so far I have'nt seen that only heard about it.
Also think more into what's going on, did you have a spy in an enemy city then a Roman faction took it over and later got caught by the Romans.
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