Terran Empire modeled on the Roman Empire. SM Stirling presents a New British Empire in an alternative timeline where:
"The physician stared in appalled wonder at the work ahead of him, then darted forward, ignoring the King-Emperor for the more seriously wounded behind him and calling for his assistants and their supplies.
"Charles glanced after him. 'I like that chap's priorities,' he said."
-SM Stirling, The Peshawar Lancers (New York, 2003), p. 454.
Charles is the King-Emperor. I also like the MO's priorities. In Britain today, if a Duke and his valet are trapped inside a burning building, then, to the Fire Brigade, they are two living bodies, both to be rescued as quickly as possible. Physical danger removes the distinction between nobility and commoners. It is good to see a King-Emperor who knows that, when others are in greater need of medical treatment, his rank counts for nothing.
Civilization can, of course, be reorganized without such ranks. But, as long as the ranks exist, they must be recognized as social conventions and nothing more.