Revocation of nobility
Revocation of nobility is the removal of the noble status of a person.
It should be distinguished from the concept of dérogeance ("derogation" of nobility), which, e.g., in the context of French history, led to removal of the privileges of nobility, but not necessarily the right for nobility itself. In particular, the nobility of descendants was not automatically lost.
Nobility could be restored by the King's Letter of Rehabilitation (Lettre de réhabilitation).
Since nobility was exempted from taxes, especially the taille, many usurped the appearances of nobility, and this usurpation could continue across generations. Therefore, in France there was a special establishment "Grand Inquiry into Nobility" Grande enquête sur la noblesse, which was in force during 1666–1727. This was accompanied by various edicts which declared certain elements of the outfit (heraldry, armaments, decorations, etc.) to be permitted only for nobility. Revocation of usurped nobility was accompanied with heavy fines.
In addition to real usurpation, inquiries were made into hereditary nobility: unless the nobility was given by a Letter of Ennoblement, according to Grande enquête one had to prove that at least four generations of his ancestors enjoyed the noble status.
In Poland existed a practice of nagana szlachectwa, which was questioning the nobility by any accuser.
- "Derogeance" Archived 2012-01-11 at the Wayback Machine, Dictionnaire encyclopédique de la noblesse de France, Nicolas Viton de Saint-Allais, Paris, 1816
- Voir Chérin, "Abrégé chronologie d’édits, déclarations, règlements, arrêts et lettres patentes des rois de France concernant la noblesse", in : Pierre Loizeau de Grandmaison, Dictionnaire héraldique, Paris Abbé Migne Publ., 1861, 
- "Contested Spaces of Nobility in Early Modern Europe", Matthew P. Romaniello, Charles Lipp (eds.), 2011, ISBN 1409405524