This paper deals with two fragments (34/35.2.25–6 and 2.33) from Diodorus’ Bibliothêkê that are unanimously considered to belong to the narrative of the First Slave Revolt in Sicily (Book 34). It is the main concern of this paper to demonstrate that they most likely did not, but instead originate from an unknown preface to Book 34. The article begins with a brief introduction into Diodorus’ prefaces and discusses the Byzantine transmission of both fragments. Against this backdrop, three main steps are consecutively applied to prove the hypothesis. First, the narrative order of both fragments within the Byzantine collections is re-examined. Furthermore, the paper establishes a thematic and argumentative relationship between the two fragments. In the last step, the structure and the style of both fragments are analysed.