The forensic expert witness is today a ubiquitous figure to be found in every field from justice to university, from public health to international policy. This multifaceted figure with varying profiles raises questions as regards objectivity, legitimacy, status and independence – the term being used for behavior patterns that cannot be reduced to a peculiar model and a single definition. Paradoxically, the current crisis in expert witness reports urges us to question the way in which former societies summoned authority figures recognized for their proficiency, experience, learning and know-how.

Focusing on the medical world of Ancient and Medieval times that have been less explored through historiography, our approach allows to highlight some forms of medical examinations beyond very different political, social or cultural backgrounds. Thanks to the diversity of tools, vocabularies, procedures or even written records, the historical approach proves to be fraught with heuristic value, provided one does not try to ascribe old origins to contemporary practices or figures but studies them in their own context.