This article examines the theoretical profile of the historian Otto Brunner (1898-1982) and his importance for the genesis of the work Geschichtliche Grundbegriffe: Historisches Lexikon zur politisch-sozialen Sprache in Deutschland (1972-1997), edited by him along with Reinhart Koselleck (1923-2006) and Werner Conze (1910-1986). It is fundamental, but also problematic, to deal with the reflections and the works of Brunner in order to comprehend the Lexikon and the experience of the “history of concepts”. From one side, without it, the experience of the Begriffsgeschichte would be for the most part undecipherable; and, from the other side, it is very problematic to take stock of the Brunner’s work with a free-value modality, especially if we take into account his relationship with the nazi regime.
Keywords: Storia dei concetti, storia costituzionale, concetti fondamentali della storia, nazismo, storia medievale, faida