The virtuous Romans appear to have been greater book-burners than the Greeks, both under the Republic and under the Empire. It was the Senate's function to condemn books to the flames, and the praetor's to see that it was done, generally in the Forum. But for this evil habit we might still possess many valuable works, such as the books attributed to Numa on Pontifical law (Livy xl.), and those eulogies of Paetus Thrasea and Helvidius, which were burnt, and their authors put to death, under the tyranny of Domitian (Tacitus, Agricola 2). Let these cases suffice to connect the custom with Pagan Rome, and to prove that this particular mode of warring with the expression of free thought boasts its precedents in pre-Christian antiquity. Nevertheless it is the custom as it was manifested in Christian times that has chief interest for us, because it is only with condemned books of this period that we have any chance of practical acquaintance. Some of these survived the flames, whilst none of antiquity's burning have come down to us. But on what principle it was that the burning authorities (in France generally the Parlement of Paris, or of the provinces), burnt some books, whilst others were only censured, condemned, or suppressed, I am unable to say, and I doubt whether any principle was involved. Peignot has noticed the chief books stigmatised by authority in all these various ways; but though undoubtedly this wider view is more philosophical, the view is quite comprehensive enough which confines itself to the consideration of books that were condemned to be burnt. Books so treated may be classified according as they offended against (i) the religion, (ii) the morals, or (iii) the politics of the day, those against the first being by far the most numerous, and so admitting here of notice only of their most conspicuous specimens. I. Of all the books burnt for offence under the first head, the most to be regretted, from an historical point of view, I take to be Porphyry's _Treatise against the Christians_, which was burnt A.D. 388 by order of Theodosius the Great. Porphyry believed that Daniel's prophecies had been written after the events foretold in them by some one who took the name of Daniel. It would have been interesting to have known Porphyry's grounds for this not improbable opinion, as well as his general charges against the Christians; and if there is anything in the tradition of the survival of a copy of Porphyry in one of the libraries of Florence, the testimony of the distinguished Platonist may yet enlighten us on the causes of the growing darkness of the age in which he lived.