Gerald was selected to accompany the Archbishop of Canterbury, Baldwin of Forde, on a tour of Wales in 1188, the object being a recruitment campaign for the Third Crusade. His account of that journey, the Itinerarium Cambriae (1191) (later followed by the Descriptio Cambriae in 1194) remains a very valuable historical document, significant for the descriptions – however untrustworthy and inflected by ideology, whimsy, and his unique style – of Welsh and Norman culture.
Gerald's biases, according to Llewelyn Williams, were well balanced. He writes that in the Itinerarium, and its companion Descriptio, Gerald was "impartial in his evidence, and judicial in his decisions. If he errs at all, it is not through racial prejudice. 'I am sprung,' he once told the Pope in a letter, 'from the princes of Wales and from the barons of the Marches, and when I see injustice in either race, I hate it.'"
- Digitised version of the British Library manuscript of Itinerarium Cambriae
- Full text of Gerald of Wales's The Itinerary of Archbishop Baldwin through Wales, as translated into English in 1806 by Richard Colt Hoare, on A Vision of Britain through Time, with links to the places named.
- Latin text of Itinerarium Kambriae (sic) in Giraldi Cambrensis Opera: Volume VI (1868) with a scholarly preface in English by the editor, James F Dimock.