Authenticating the writings of Julius Caesar

• We shed new light on the authenticity of the writings of Julius Caesar.
• Hirtius, one of Caesar’s generals, must have contributed to Caesar’s writings.
• We benchmark two authorship verification systems on publicly available data sets.
• We test on both modern data sets, and Latin texts from Antiquity.
• We show how computational methods inform traditional authentication studies.

In this paper, we shed new light on the authenticity of the Corpus Caesarianum, a group of five commentaries describing the campaigns of Julius Caesar (100–44 BC), the founder of the Roman empire. While Caesar himself has authored at least part of these commentaries, the authorship of the rest of the texts remains a puzzle that has persisted for nineteen centuries. In particular, the role of Caesar’s general Aulus Hirtius, who has claimed a role in shaping the corpus, has remained in contention. Determining the authorship of documents is an increasingly important authentication problem in information and computer science, with valuable applications, ranging from the domain of art history to counter-terrorism research. We describe two state-of-the-art authorship verification systems and benchmark them on 6 present-day evaluation corpora, as well as a Latin benchmark dataset. Regarding Caesar’s writings, our analyses allow us to establish that Hirtius’s claims to part of the corpus must be considered legitimate. We thus demonstrate how computational methods constitute a valuable methodological complement to traditional, expert-based approaches to document authentication.