One of if not the first law passed when Rome founded it's republic declared that any man who called himself king could be killed by any other man at any time with no recourse.
That's because Rome started as a revolutionary movement lmao, having thrown off the yok of Etruscan kings and later fighting counter-revolutions and Etruscan invasions (which they lost) and incursions from the Latin leauge (who liberated Rome from the Etruscans) and
after all that they declared that not a single person could call himself a king. And this was not an idle threat lol it was enforced long, long, passed the death of the republic. Cannot stress how much of Rome's founding mythos centered a hatred and distrust of absolute rulers
So the absolute rulers of Rome who inherited their role and ruled for life did not call themselves kings. They were Princeps (first citizen), Imperator (commander), Augustus (Majestic One), ect but never king. They would wear regal attire and command awe but would be killed for wearing a crown, they would tower above others but rarely on a throne
It's so silly I love it lol
