Growing interest in the archive as an object of study for queer criticism justifies closer attention to the concept of provenance. For archivists, provenance imparts a fundamental measure of integrity to archival collections by certifying their origin and proper order. Record origin and order, however, rely on authorial identity to establish authenticity, placing provenance in tension with queer theories that describe subjectivity as polymorphous, not fixed. That tension leads Roger Casement’s official reports on the atrocities committed against rubber gatherers in South America to use provenance as a credible—rather than strictly authentic—narrative structure for publicizing British investigations of imperial violence. Recognizing provenance as a practice of representation invites reconsideration of Casement’s notorious private diaries, which document his sexual interest in large penises. Instead of simply providing evidence of homosexual identity, the diaries show how impersonal fantasy becomes a constituent part of archival practice.