Between this MS. and the first known Christian book work there may have been many that have now perished, and which, had they remained, would have marked the transition more gradually. But even as they stand there is no appreciable difference between the earliest monuments of Christian art and those of the period which preceded them. Nor shall we find any break, any distinct start on new principles. It is one continuous series of processes--the gradual change of methods growing out of experience alone--not owing to any change of religion or the adoption of a new set of theological opinions. Of course we shall find that for a very long time the preponderance of illuminated MSS. will be towards liturgical works; and we shall also find that where the contents of the MS. are the same the subjects taken for illustration are also selected according to some fixed and well-known set of rules. We shall see the explanation of this by-and-by. The first example of a Christian illuminated MS. is one containing portions of the Book of Genesis in Greek preserved in the Imperial Library at Vienna. It is a mere fragment, only twenty-six leaves of purple vellum--that is, bearing the imperial stain--yet it contains eighty-eight pictures. We call them miniatures, but we must remember that by "miniator" a Roman bookseller would not understand what we call a miniaturist; and, as we have said, the word "illuminator" was not then known. This Vienna Genesis is not introduced among illuminated books, therefore, because of its miniatures--pictures we prefer to call them--but because the text is nearly all written in _gold_ and _silver_ letters. The pictures, according to the Greek manner, are placed in little square frames. They were executed, no doubt, by a professional painter, not without technical skill and not hampered by monastic restrictions. The symbolism which underlies all early art is here shown in the allegorical figures (such as we shall meet with again in later Byzantine work), which are introduced to interpret the scene. We see the same thing in the catacombs. Being a relic of great importance, this Genesis codex has been often described and examples given of its pictures. Of course, in a little manual like the present we cannot pretend to exhibit the literature of our subject. We can scarcely do more than refer the reader to a single source. In this case perhaps we cannot do better than send the inquirer to the Victoria and Albert Museum at South Kensington.