High Nobility

The High Nobility are the core of the Imperial aristocracy. They hold most power and work under the greatest responsibility in the Imperial system. They are members of old families that tend to be both powerful and wealthy that have been the backbone of the Imperium for generations.
New high noble titles are extremely rare. Generally new titles are granted for winning wars, boosting the economy by trillions of credits or being pivotal in bringing a new system into the Imperium. The service must be something way above and beyond the call of normal duty, not just a personal achievement.
High nobles are directly responsible for administering Imperial territories in the name of the Emperor and exercise the Imperial Mandate there. They uphold Imperial law through their command of Imperial resources. High nobles are able to raise a corps of troops, called huscarles, to support their authority directly. Barons are the lowest of the high nobles, and their titles must be hereditary. Viscounts, counts and dukes are, by definition, high nobles.
High noble titles are always with Imperial worlds, almost having a fief on a world within their demesne. Viscounts and higher nobles are usually associated with demesnes that span multiple star systems.

Qualifications

High nobles must be a baron, marquis, viscount, count, duke or archduke.