In international criminal tribunal discourse, appeals to history and legitimacy are omnipresent. This article addresses the widespread practice of combining these appeals into one narrative. It analyses how international prosecutors engage with justifying the legitimacy of trials through the invocation of a tribunal's own history. The scrutiny of such 'auto-histories' as a specific form of history-telling illuminates an overlooked dimension of trials as fora for writing history. The opening statement is a perfect opportunity for constructing and communicating auto-histories. A comparative study of opening statements at the International Military Tribunal, the Special Court for Sierra Leone and the International Criminal Court reveals a recurrent, self-justifying narrative where both rootedness in history and a break with the past are key to singing the tribunal into existence as a crucial mechanism in the transition from chaos to peace. The connections between auto-histories at different tribunals show how legal practitioners discursively contribute to constructing the international criminal law's identity by relying on both origins and future.