Note on Nobile Titles
Broadly, the Sollan Empire is divided into four primarchates:
one in Orion;
one in Perseus;
one in Sagittarius;
and most recently, one in Centaurus.
Efforts to establish a fifth primarchate in Norma were stymied by the Cielcin invasion, and following the Battle of Gododdin and the death of Emperor William XXIII Avent, the Norman colonies remained unincorporated and under the oversight of the Centaurine primarch at Nessus.
The primarchs are appointed by the Emperor, who is himself the Primarch of Orion.
Each of the Imperial primarchates is subdivided into several provinces,
each governed by an Imperial viceroy appointed by the primarch. Nominally, the title of viceroy is an appointed one, but in practice the viceroyalties of many provinces pass from parent to child,
as do the palatine titles of archduke, grand duke, duke, marquis, count, viscount, and baron. Each of these lords rules a palatinate
Archons serve these palatine lords in administering districts of said demesnes.
comprising their planetary demesnes and the attendant solar systems.
The difference between a baron and a duke, for example, is determined by the relative import of the palatinate in question.
They may pass their holdings on to their children, though many archons are appointed and are little more than governors. An appointed archon, as in the case of a colonial consul, is said to rule a fief, not a demesne, as his claim to said territory expires in the event of his death and does not pass to his children.
Empire of Silence - Index of Worlds: A Note on Astrography
*** Text formatting added to original text to help distinguish the levels of Palatine Nobility.