lead us to suppose that he was already famous for his scholarship before he went abroad. An additional reason for believing that he had acquired a reputation as a scientist is the fact that he is called in the annals Virgil or Fergal the “Geometer.”[483] _Dicuil_ (d. 825 A.D.) is another instance of an Irish scholar who was interested in secular studies. His chief claim to fame rests on a Latin tract entitled _De Mensura Orbis Terrarum_.[484] As the name would suggest, this was a work of geography in the sense that the term is now used. The internal evidence leaves no doubt as to the Irish birth and education of the author. He speaks of _nostri Scoti, nostra insula Hibernia_, alludes to the Irish poet Sedulius whom he styles _noster Sedulius_ and he shows an accurate knowledge of the islands near Britain and Ireland.[485] He tells that a certain Suibneus (in Irish Suibhne anglicised Sweeney) was his master to whom under God he owed whatever knowledge he possessed. This Suibhne has been identified with Suibhne, abbot of Clonmacnoise, who died 810 A.D.[486] This would suggest that Dicuil was a pupil of the famous school of Clonmacnoise. He derived his material from three sources: 1. He utilised the report of the Theodosian survey. He tells us that he made it the basis of his work because though vitiated by false MSS. it was less faulty than Pliny especially in its measurements. 2. He utilised the works of previous geographers. 3. He made several interesting additions to existing knowledge which he derived from trustworthy accounts of Irish monks who were the greatest travellers of the time. The list of authors from whom he borrowed is very large, including Pliny, Solinus, Isidore, Virgil, Crosius, Servius, Hectateus, Homer, Herodotus and other Greek writers.[487] Dicuil is the first writer to refer to Iceland, which he describes under the name Thule from an account given to him by some Irish monks who visited that island about thirty years previously (c. 795 A.D.) and remained there from February to August. He was also the first to give authentic information about the Faroe Islands, which were visited by Irish hermits a hundred years before, but were forsaken on account of the piratical incursions of the Northmen. The truth of these interesting accounts is proved in two ways: 1, the tolerably exact statements as to the length and shortness of the days could only be determined by a resident of the place; 2, from northern and independent sources we learn that the first Norwegian settlers who were of course pagans found Christians whom they called _Papar_. These Papar left Irish books, croziers, bells and other things behind them when they went away.[488] When describing the Nile he introduces the narrative of a brother Fidelis who with a party of priests and monks made a journey from Ireland to the Holy Land.[489]