So, my understanding is that European use of the terms ‘Emperor’ and ‘Empire’ come from the Roman Empire. That when subsequent rulers claimed the title of Emperor they where trying to tie their rule back to the Roman Empire as a way to confer upon themselves.
Where there any antecedents to the Roman usage of emperor? Or was the term novel when Cesar used it? (I know he didn’t claim king because of prior Roman experiences with kings)
Presumably when Europeans came into contact with countries with what we call an ‘Emperor’ is then an exonym, a name bestowed upon someone by an outsider
the crux of my wondering. What decided if a ruler would be called be called emperor or king? Size of the nation? Power? Divine status? Did countries outside of Europe have an understanding of a difference between a king and an emperor or is that simple orientism. That other cultural groups had entirely different societal constructs and we just labelled the highest ranking guy emperor for western convenience. I’m thinking in particular of China and Japan.
I don't really know what made the rulers of the Middle Ages/Modern period choose the title king or emperor, but I can answer your first question. The word emperor is actually the English derivative of the Latin word imperator. That was one of Augustus' titles. In the Republic imperator had been derived from the Latin verb imperare, which means 'to order, to command' and a high ranking military officer would be said to be an imperator. Augustus chose this pre-existing title to portray him as a regular Roman commander and a first-among-equals rather than being in a new despotic position.