Below is an example of the hierachy of noble titles, useful for building NPCs and fantasy worlds.

Rank	Title
1st	Title:  Emperor/Empress
2nd	Title:  King/Queen
3rd	Title:  Duke/Duchess
4th	Title:  Prince/Princess
5th	Title:  Marquess/Marquise
6th	Title:  Earl or Count/Countess
7th	Title:  Viscount/Viscountess
8th	Title:  Baron/Baroness
9th	Title:  Baronet
10th	Title:  Knight