The claim that the illicit trade in antiquities is the third largest, second only to arms and narcotics, is widely repeated. But where does this claim originate and what is the evidence for its veracity? The authors present a ‘stratigraphic excavation’ of the claim by systematically searching through academic articles, popular press and policy literature to reveal the factoid's use and reuse over the past five decades. The authors find that the claim is not based on any original research or statistics, and it does not originate with any competent authorities. The analysis demonstrates how the uncritical repetition of unsubstantiated ‘facts’ can undermine legitimate efforts to prevent looting, trafficking and illicit sale of antiquities.