Other examples have a square frame filled with the latter kind of scrolls and foliages, leaving a sort of open panel in the centre, in which is placed a small scene of sacred history or perhaps of country life. Sometimes the title, in golden letters, is surrounded with medallions containing heads of Christ and the Virgin, apostles, and saints. The peculiar interlacing bands of violet, yellow, rose, blue, etc., which are still often seen in Russian ornament, are also features of these Byzantine MSS.; but most of all is the lavish use of gold. Perhaps the fact most to be remembered about these MSS. is that the painters of them worked in a manner that was absolutely fixed and rigid, the rules of which are laid down in a manual called the _Guide to Painting_, a work which has been translated by M. Didron. So fixed and unalterable, indeed, is the manner that there is absolutely no difference to indicate relative antiquity between a MS. of the eleventh century and one of the sixteenth or even later, we might almost say, of the present day. In the matter of saint-images this is strictly true. CHAPTER VI CELTIC ILLUMINATION Early liturgical books reflect the ecclesiastical art of their time--This feature a continuous characteristic of illumination down to the latest times--Elements of Celtic ornament--Gospels of St. Chad--Durham Gospels--Contrast of Celtic and Byzantine--St. Columba--Book of Kells--Details of its decoration. In the earlier centuries of Christianity, when liturgical books were the chief occupation of the illuminator, it will need little pointing out to demonstrate that the page of the illuminated manuscript, where it contained more than the mere ornamental initial, was simply a mirror of the architectural decoration of the church in which it was intended to be used. Where the church enrichments consist, as on the Byzantine basilicas, of panellings, arcades, and tympana of gilded sculpture in wood or stone, with figures of saints, the pages of the Gospel-book bear similar designs. Where, as in the Romanesque, they are rich in mosaics, and fretted arcades interlacing each other, so are the illuminated Lives of the Saints, the Menologia, Psalters, and Gospel-books. Where, as in the Gothic cathedrals of the West--of France, Germany, or Italy--the stained glass is the striking feature of the interior, so it is with the illumination; it is a "vitrail"--a glass-painting on vellum. On this latter point we shall have more to say when we reach the period of Gothic illumination.