“Nobility of the Robe” and “Nobility of the Sword,” two expressions commonly repeated in historiography of the nobility of the modern era, are not simple social descriptions. Their chronologically staggered appearance, and the development of their usage in the seventeenth century are the result of the transformations of the Second Estate, transformations which themselves stemmed from monarchical policy (development of the venality of offices, desire to control the definition of nobility) and from struggles for power among the elites of the realm. A social history of their uses should be confronted with an analysis of the social careers of Second Estate families. This would show to what extent these expressions are above all ascriptions referring to ideological confrontations, to value judgments about what the nobility should be, and, finally, to a desire to separate social spaces that were, nevertheless, porous. Such a history clearly shows how terms designating conditions become categories designating groups based on classification. These were changes that brought about great consequences as much for the future of noble families as for the concept of the nobility itself.