Apart from that in daily use among the people, we may, however, look upon the glass made during the first four or five centuries of Arab domination as on the whole following in the wake of the carvings in hard stone, above all in rock crystal, then so much in vogue. During the whole of this period the Saracens had hardly developed any well characterised art of their own: they followed in this, as in so many other matters, the traditions of the countries in which they dwelt. At this period their art was at best but a mingling of Byzantine and Sassanian elements. But before the end of the twelfth century a great change had come about, and during the course of the next century there had arisen a definite style—one that has remained ever since the type of what we know as Saracenic art. It would be impossible to dissociate this change from that which took place in the West about the same time. But the Gothic art that sprung up in the land of the Franks was but one phase of a continuous evolution, while the wonderful outburst that had in the main its centre in Cairo, became either locally stereotyped or shared the decay and neglect that overtook other branches of Mussulman civilisation. So far as the art of glass is concerned, we may note in the thirteenth century a strange contrast between the East and the West. For while in both lands the material was applied essentially to supply a scheme of colour in decoration, in the West its use was restricted to the stained glass in the windows of churches; in the East the source of colour was obtained from translucent enamels applied to the surface of glass lamps and vases. The Saracens, in the stained glass of their windows, merely followed in the old Byzantine lines; the pierced framework of plaster, filled in with fragments of coloured glass, is but a development of the marble _chassis_ of the Romans and the later Greeks. In the West, on the other hand, the art of building up pictures by means of segments of glass was rapidly developed, while the ‘hollow ware,’ the _verrerie_ in daily use, had, as we have seen, received little attention, and it was reserved to the few precious pieces of enamelled glass brought from the Holy Land to find a place along with the plate and jewellery in the inventories of princes.