I also see the Romulans as the equivalent of the Roman Empire, especially in the TOS era, as they have Roman/Latin titles: praetor, centurion, etc. Romulus and Remus, according to myth, were the founders of Rome raised by a she-wolf that were in conflict w/ one another w/ Romulus becoming the king after killing his brother. Remus is subjugated and viewed as second-class citizens & slaves (at least up to Nemesis). This correlates to the mythology.
They are Machievellian schemers (TNG-era) and view themselves as superior to everyone - a Roman virtue. However, comparions to modern China & N. Korea can be made: they are isolationist & distrust outsiders. The Praetor & Senate aspect of its government is Ancient Roman in style, especially during the Imperial era as emperors were occasionally assassinated, committed suicide, insane (Caligula, etc.), and power hungry.