France was already famous for its glaziers: for instance, when in A.D. 680 the Abbot, Benedict Biscop, glazed the windows of the monastery at Monkwearmouth, we read in Bede that "he sent messengers to Gaul to fetch makers of glass (or rather artificers) till then unknown in Britain.... They came, and not only finished the work required, but taught the English nation their handicraft"; and it is probable that the French glaziers, chafing under the limitations of their art, called in the aid of the Venetian enamellers. It is noteworthy that no attempt seems to have been made to use transparent coloured enamel on glass. That mistake was reserved for the decadence of the art seven hundred years later. Perhaps experiment convinced them that enamel colour could never hope to rival the depth and richness of coloured glass, and the glazier would realize that what he wanted of the enameller was not colour but black, to modify and enrich the colour which his glass already gave him in full measure. In this book, therefore, the word "enamel," when used in connection with glass, must be understood to refer, unless coloured enamel is specifically mentioned, to this brown opaque enamel or "paint," as glass-workers call it. [Sidenote: Cloisonné.] But the enameller's art had another influence on that of stained glass. A form of enamelling developed at Constantinople and practised at Limoges was that known as "cloisonné." In this, narrow strips of metal are soldered edgeways to the groundwork and the spaces between are filled with differently coloured enamel, the different colours being thus separated by strips of metal. When the enameller's attention was first turned to glasswork, in which different coloured pieces of glass were separated by strips of lead, he must have been struck with the similarity of the two arts, and have perceived that the style of design already developed in enamel could be applied with little change to glasswork. This probably explains not only the apparently sudden birth of the art fully formed, but the strongly Byzantine character of the design in the earliest work, the enameller's art having been brought, as we have seen, from Constantinople by way of Venice.[3] What, then, is the oldest "stained-and-painted" glass in existence? At Brabourne in Kent there is a small window, of which a coloured tracing may be seen in South Kensington Museum, which may belong to the eleventh century. It consists of a simple pattern of white glass and leading, with small pieces of colour inserted at intervals. Some of these latter, however, have been formed into rosettes of simple design by means of opaque enamel, which is the only painting in the window at all. Whatever the actual date of the window, I think it is not unlikely that it shows the manner in which enamel painting and glazing were first combined. [Illustration: PLATE IV "NOË IN ARCHA," FROM THE NORTH CHOIR AISLE, CANTERBURY Twelfth Century]