27Cambrensis, Giraldus. The Historical Works, Containing The Topography of Ireland and the History of the Conquest of Ireland, Tr. by Thomas Forrester; The Itinerary through Wales, and the Description of Wales, Tr. by Sir Richard Colt Hoare. Ed. Thomas Wright. London: George Bell & Sons, 1905. 279-80.
O'Donovan (December 12th 1837) attributes the spread of the false Colm Cille prophecy to Giraldus Cambrensis: "Cambrensis states that that the prophecies of Colbumbkille were preserved in books in his time and that the Irish people believed in them with the most implicit faith." (O'Donovan, John, Eugene O'Curry, Thomas O'Connor, and George Petrie. Letters Containing Information Relative to the Antiquities of Kildare II (v. 13). Collected during the Progress of the Ordnance Survey, 1834-41, Ed. Michael O'Flanaghan. Bray. 1927. 80.) However, in this online translation of Giraldus' Expugnatio Hibernica ("Conquest of Ireland") there is no mention of the Valley of the Black Pig in the prophecy attributed to St. Colm Cille. It may be that O'Donovan and others erred in identifying Giraldus" account of Colm Cille's prophecy with the Valley of the Black Pig.