Johannes Brahms’s well-known historical consciousness took a particularly formative turn in the mid-1850s when he embarked upon a self-imposed hiatus from composing to deepen his knowledge of the music-historical past. This conscious embrace of historical study was characteristic of his time. Following the 1848 Märzrevolution, a growing contingent of German intellectuals, sceptical of the more speculative teachings of philosophy and theology, became increasingly receptive to the concrete lessons of history. Brahms’s reading habits suggest his inclination toward a politics of historical knowledge closely associated with the ‘Prussian School’. The writings of these historians, including Johann Gustav Droysen, Henrich von Sybel and Heinrich von Treitschke, exhibit a blend of idealist philosophy and dogmatic empiricism oriented above all toward the goal of legitimating German national unification under Prussia. Particularly influential was Sybel’s seven-volume Die Begründung des deutschen Reiches durch Wilhelm I (The Founding of the German Reich through Wilhelm I), completed in the 1890s. Brahms, a Hamburg-born sympathizer of Prussian Kleindeutsch nationalism, who was a permanent resident of the Austrian capital of Vienna for the last 26 years of his life, was uniquely situated in relationship to the ‘German Question’. His well-marked copy of Sybel’s magisterial text adds illuminating granularity to our understanding of his personal and political values and ruminations on history spanning four decades. Brahms’s reading of Sybel makes legible a longer trajectory stretching from his ‘years of study’ in the 1850s, conveying how the studious historicism of his youth is best understood as an aesthetic stance densely interwoven with, and at the end of his life ratified by, the cultural and political agendas of Prussian School ideology and the meanings of the past forged in the crucible of the German historical imagination.