Christianity is believed to have been introduced into Orkney before the Norwegian conquest by King Harold Harfager, in 895; but the race who inhabited the country at that period are said to have been extirpated or driven out by the Scandinavians, who were worshippers of Odin and Thor. In the end of the tenth century, the King of Norway, Olaf Tryggveson, renounced Paganism for Christianity, which he forced both on Norway and Orkney at the point of the sword. M. Depping, in his _Histoire des Expéditions Maritimes des Normands_, tom. ii. p. 60. ed. 1826, states that Sigurd, the second Earl of Orkney (whose brother Ronald, Earl of Mære, the first Norwegian Earl of Orkney, was the common ancestor of the Earls of Orkney and Dukes of Normandy), drove the Christians out of Orkney. This was towards the beginning of the tenth century. It has been overlooked by Barry, the local historian, or unknown to him, who mentions (p. 123.) the introduction by King Olaf Tryggveson as either the first introduction, or at least the final establishment of the Christian religion. I have looked into Torfæus' _Orcades_, the Orknayinga Saga, and the Sagas of the two kings, Harold Harfager and Olaf Tryggveson, in Mr. Laing's translation of Snow's Hermskringla, and have not found the expulsion of the Christians by Sigurd mentioned in any of those works. Will some of your learned correspondents be so obliging as to point out M. Depping's authority for this fact? I have just now fallen in with a curious example of the rude Christianity of the Northmen, who worshipped both Thor and Christ, and the passage is perhaps worth quoting. Torfæus, in his _Orcades_, p. 15., mentions a Scandinavian chief called Helgius, who lived in Iceland about 888, and says: "Christianis sacris quibus infans initiatus est, per totam vitam adhæsit, valde tamen in religionis articulis rudis; nam Thorem, ad ardua negotia, itineraque maritima feliciter expediunda, invocandum, cætera Christum dictitavit, tanquam cum Thore divisum imperium habentem. Simile Witichendus Monachus et Sigebertus Gemlansensis, de Danis, in primis religionis incunabulis, prodidere." W. H. F. THE ROMAN INDEX EXPURGATORIUS OF 1607. This work, both in the original edition, and in the reprint of Bergomi, 1608, is reputed to be of extreme rarity. Mr. Mendham, in his _Literary Policy of the Church of Rome Exhibited, in an Account of her Damnatory Catalogues or Indices, both Prohibitory and Expurgatory, &c._, 2nd ed., London, 1830, calls it "perhaps the most extraordinary and scarcest of all this class of publications," p. 116., while all of the class are known to be by no means of common occurrence. Clement (_Bibliothèque Curieuse_, art. "Brasichellensis," v. ccvii.) designates the Roman edition as "_extrêmement_ rare;" and (note 48., p. 211 a.) says of the other, "cette édition de Bergame est encore plus rare que celle de Rome."