How do I do that again? I've done PBEMs before so I know I should know this... But yeah, that would be helpful.

I just took Rome in my short Greek campaign; I think it was city # 12. No crash, no problem. Although another difference was in this Greek campaign, the Senate still held Capua (they'd bribed it from me several turns before) -- so the Senate faction was not destroyed when I took Rome. And taking Rome this time didn't prompt a victory video. So I wonder if it's just a result of taking Rome as your final city.