XCIX. But, above all, it is necessary to find out the natural disposition of an author. There are some, who so strikingly display the character of men of truth and sincerity, that they command our belief of them, even when they speak in favour of the party they are attached to. In this elevated point of view, we may venture to place Philip de Comines, our Mariana, and Henry Catherinus. But to acquire this knowledge of authors, demands singular perspicuity; for, although it is generally said, that in the writings of authors we may read their genius and disposition, we should reflect, that these are much more easy to be disguised by the pen than with the tongue. It is well known, that Sallust was a man of debauched morals; but notwithstanding this, there is scarce any other author, in whom we find such frequent declamations against vice. C. The degree of reading and extent of historical information that is required, either to write or make a just judgment of any history, is very great. It is not only necessary to know exactly the religion, laws, and customs of the nations to which the events relate, in order to be clear whether they are repugnant to or correspondent with them; but it is also frequently necessary to know those of other nations, because it often happens, that the circumstances of one kingdom are blended with those of another, either by commerce, wars, or a thousand other accidental contingencies. SECT. XLIII. CI. But what above all makes writing history a difficult task is, that, in order to be a historian, it is necessary for a man to be much more than a historian. This, which may appear a paradox, is not so, but a most true position: I mean, that a person can’t be a perfect historian, who has not studied other faculties besides history; because, in various instances, a knowledge of other faculties discovers the falsity of some historical relations. The understanding geography, for example, no one can deny to be exceedingly necessary. Polybius and Diodorus Siculus, were so diligent in this matter, that before they wrote their histories, they travelled over the kingdoms and countries to which they related. Now-a-days this labour is not necessary, because the numbers of geographical books and maps at present extant, although they are not minutely exact, are sufficiently correct to make this trouble needless.