See, for example, the Proffwydolyaeth yr Eryr ("Prophecy of the Eagle" : Welsh) from the Llyfr Gwyn Rhydderch (The White Book of Rhydderch: see Other Works) and the Welsh poem The Dialogue of Arthur and Eliwlod. Geoffrey of Monmouth refused in the Historia Regum Brittaniae [ii.9] (see Other Works) to translate the prophecies of an eagle given during the building of Shaftesbury. Geoffrey implies [xii.18] that the "Auguries of the Eagle" he refuses to translate was one of the great books of British prophecy used in the 'Dark Age'. Such a book may or may not have included the Proffwydolyaeth yr Eryr, as prophecies tended to be somewhat fluid. For example, Crick* notes that the Auguries may be those attributed to "Merlin Sylvester" by Gerald of Wales in his Expugnatio hibernica ("Conquest of Ireland" : 1187-8 C.E.).