Cambrensis tells us another fact which shows to what degree of perfection the art of illumination was carried in the Schools of Kildare. "Amongst all the wonderful things at Kildare," he says, "nothing appears to me more wonderful than that admirable book written as they say at the time of the Virgin from the dictation of an angel. This Book contains a Harmony of the four Evangelists according to St. Jerome, in which there are nearly as many different figures variously illuminated in colours as there are pages. In one part you may behold the countenance of majesty divinely depicted; in another the mystic emblems of the Evangelists, some represented with six, others with four, others with two wings; here an eagle, there a calf, now the face of a man, again, that of a lion, as well as an almost infinite number of other figures, which if you merely glance at in the usual way, without taking notice of, they will appear to be blots rather than ligatures, and displaying nothing exquisite where, notwithstanding there is nothing but what is exquisite. But if you examine them sharply and try to penetrate their beauty, you will be able to note the delicate beautiful minute interlacings, in colours still fresh and bright so that you would be led to believe that they were indeed the work of an angel rather than of man. The oftener and more carefully I have examined them the more was I struck with new wonder, and each time I saw fresh subjects to call for admiration." Giraldus goes on to tell the story of the writing of the book as it was told in his time and concludes: "In this way was the Book written, the angel showing the pattern, St. Brigid praying and the scribe copying."

This description of the Book of Kildare answers the Book of Kells, and goes far to show that the two Books were of equal artistic value. Petrie and Todd are of opinion that the Book of Kells is the identical book described by Cambrensis, and there is a growing tendency towards that opinion.