FLTD: Setting: Titles

Long before Paraceln's Age, power in Komaru was much more centralized, with a strong king, clear lines of fealty, and a shortage of history. Back in those days, there were two true levels of title:

Duke/Duchess: Ruled all of a family's lands, and owed fealty to the king.
Count/Countess: Ruled a portion of a family's lands, and owed fealty to the duke that granted his or her lands lands.

Dukes divided their duchy into counties and parceled them out to Counts; Counts divided their counties into baronies, and parceled them out to Barons, who did the actual village-level administration.

Over time, the families subdivided, splitting into cadet branches as they jockeyed for power. As the families branched, treating them as a single duchy became unwieldy. To create meaningful titles, the original Duke claimed some choice land, all of the Counts were promoted to duke (note lower case), and the new dukes divided their lands into counties and appointed counts to rule them. Frequently, these counts had previously been loyal Barons, and they in turn created their own barons.

Time passed, and Komaran society continued to evolve. First, some of the new counts got free of their feudal ties to their dukes, and instead swore fealty directly to the king. These counts became the first Earls/Marquises (two words for the same title, although Earl fell out of fashion). Second, some of the barons got free of their feudal ties to their count, or even to their count and their duke. These independent barons became Viscounts. As more time passed, the king's powers waned, and the titles became something the families distributed like appointed offices. Today, the following is true:

Dukes and duchesses rule duchies, and are only technically answerable to the Crown Prince and the Royal Council. They hold vassal counts or countesses. They are "Your Grace."
Marquises, marquesses, and other variations of the title rule marquisates/marches/earldoms/duchies (if they're arrogant), and are only technically answerable to the Crown Prince and the Royal Council. They do not hold vassal counts or countesses. They are also "Your Grace."
Counts and countesses (and countessas and so forth) rule counties, and have a superior duke or duchess. They are "Your Excellency," or "Your Excellence."
Viscounts and viscountesses rule viscounties, and may or may not have a superior duke. They do not have vassal barons. They are also "Your Excellency," or "Your Excellence."
Barons and baronesses rule baronies. They are created at the whim of anyone holding a title of count or greater, and are not assigned by the Royal Council. They hold part of their superior's lands, and administrate their holding for their lord. Obviously, they do not have vassal barons. They are addressed as "Lord," or "Lady."

It is always polite to refer to someone by their given name with the suffix -sama, indicating that they are your superior. Among equals or inferiors, adding the suffix -san to the given name indicates respect. Referring to a noble by the place name of their title is generally polite, particularly among traditional nobles. In theory, this indicates a strong bond between the noble and the land he holds.