Giraldus Cambrensis is renowned for his historical and ethnographic works on Ireland and Wales. His sources for these texts are less clear, and the purpose of this article is to examine his usage of classical, biblical, and patristic texts as sources for quotations in the Itinerarium Kambriae, with reference to his other works when necessary. It argues that the quotations which appear in the text as altered from the original source are not the result of misquotation or faulty memory, as has been claimed previously, but of deliberate reworking to fit the context and the argument of the passage in which the quotation appears. This deft manipulation of quotations to support his argument reveals a level of rhetorical skill and awareness not previously acknowledged. The article also finds attribution for several quotations whose origins were previously unknown. As Giraldus was in the habit of adding quotations and self-quoted passages to his works over time, this discussion is followed by an examination of his revisions to the Itinerarium Kambriae and the implications of these revisions on the transmission of his work.