This workshop is the third and final meeting of the AHRC Research Network “Writing a New History of Treason.” Building on our previous discussions about the legal frameworks and cultural representations of treason, we now turn to the question of what treason does over time. Accusations of treason are not contained by the moment of their articulation. They generate consequences that extend far beyond the courtroom or the scaffold – shaping political cultures, legal traditions, and collective memory across generations. Treason trials produce martyrs and villains; sites of punishment become places of heritage and contestation; legal categories forged in one context migrate to others, often with lasting effects. The heritage of treason is never settled: cases are remembered, forgotten, rehabilitated, or reinstrumentalized according to changing political needs. This workshop explores the afterlives of treason – how accusations, trials, and punishments have reverberated through different societies, how treason has been inscribed in legal archives, built environments, and national narratives, and how its long-term impact has been contested from antiquity to the present.