A stylometric analysis of the relative strength of notarial and inquisitorial stylistic markers in the Bologna inquisition register (1291–1310)

Scholarship on inquisition registers (collections of heresy trial documents) has long debated the extent to which these texts reflect the voice of the deponent (witness under interrogation) or the inquisitor. Much less attention has been paid to the contribution of notaries. As trained legal professionals entrusted with public authority, notaries were instrumental in moulding the oral proceedings into the final written product, mediating between vernacular speech and Latin documentation, selecting information, standardizing terminology and narrative, and implementing the formal requirements of legal proceedings. Their collaboration with inquisitors, who directed the questioning and controlled the focus of depositions (written records of witness interrogations), offers a unique lens onto their co-authorship of these texts. Using the Bologna inquisitorial register (1291–1310), we employ a stylometric approach that utilizes corpus masking, supervised learning, a custom feature selection of potential inquisitorial and notarial markers, and a contrastive feature analysis mainly based on measures of role distinctiveness, feature consistency, and variability. In so doing, we create a dataset of linguistic patterns that are consistent and distinctive for notaries and inquisitors in the register. Subsequent qualitative analysis reveals patterns that can be clearly linked to narrative and discourse types, while certain patterns are found to be distinctive for either role. A strength analysis quantifies the relative contributions of notaries and inquisitors in the register, respectively, showing differences in predictive dominance favouring inquisitors in the overall average (42.4:57.6), but revealing significant variation among individual collaborations. We conclude that our method holds promise for the analysis of role-based stylistic markers in historical legal texts, especially those verbalizing oral proceedings. This is a preprint version of an article submitted to Digital Studies / Le champ numérique.