I have occasion to render a cordial personal acknowledgment to the well-known scholar the Rev. Thomas J. Shahan, of the Catholic University of America, for most friendly service and valuable suggestions. I owe thanks also for friendly counsel received from the Rev. A. A. Lambert, of the Paulist Fathers. With the expectation that these volumes will be used chiefly for purposes of reference, it has seemed desirable to arrange the material according to the cyclopaedia method, under certain main headings with sub-headings for the special divisions of each subject. Such an arrangement involves, of necessity, some repetition, but it is hoped that the convenience of securing for the presentation of each subject division a larger measure of completeness, may outweigh the annoyance, from the literary point of view, of an occasional reiteration. G. H. P. NEW YORK, October, 1906. ERRATA. _Page._ _Line._ XVIII. 27. _For_ Bibliotheca, _read_ Bibliothecae. XXI. 24. „ erudita, „ eruditae 161. 28. „ Ferdinand, „ Ferdinandi 166. 23. „ Diologis, „ Dialogis 180. 3. „ Tridentinae, „ Tridentina 201. 32. „ Expurgatur, „ Expurgatae 201. 33. „ Prodierunt, „ Prodierint 217. 21. „ Selectissimum, „ Selectissimorum 236. 21. „ Imamorato, „ Inamorato 241. 15. „ Venito, „ Veneto 242. 2. „ Aliquot, „ Aliquod 242. 2. „ Placatum, „ Peccatum 242. 5. „ Indictis, „ in dictis 243. 9. „ Emendationis, „ Emendatioris 245. 13. „ Regularam, „ Regularum 252. 21. „ Hominis, „ Hominibus 253. 20. „ Dèque, „ Deque 268. 9. „ Indices, „ Indicis 290. 14. „ Expurgatae, „ Expurgati 290. 14. „ Permittentur, „ Permittuntur 292. 6. „ Fidelitas, „ Fidelitatis 292. 7. _After_ nunc, a _comma_. 292. 8. _For_ Principo, _read_ Principe 294. 2. „ Veribus, „ Viribus 299. 20. „ Indici, „ Indice 308. 22. „ Siu, „ Sui 320. 19. „ Sine, „ Sive 331. 35. „ Erasimana, „ Erasmiana 336. 4. „ Haes, „ Haec 345. 19. „ quorumdam „ quorundam 352. 5 and 12. „ Bailliet, „ Baillet 352. 13.