What is another word for totalitarianism?

Help me find my word please. I’m having a brain fart ladies and gents.
I used a word in a debate with my boss today regarding oppressive regimes and totalitarian governments. I want to research the word that rolled off my tongue to check for accuracy but my brain is stuck on finding the said word.

This will help, it is the name of an ancient dictator I think. Possibly ancient Greek.