how a Roman emperor crowned?

[M. Demetrius]

I don't think they ever returned to calling the Imperator (commander, or the one who issues commands) or Dictator (lit. speaker, but figuratively "the one who says what will happen" in practice--a Republic office put on a Consul for a finite period of time) "King".

Dictator for Life was the last title that J. Caesar held. Didn't do him much good, though. They really didn't want a king any more. That was in their DNA almost.