field that was denied to painting, reached its most splendid development.
Though simpler styles of this art had been practised earlier, in its full development it is peculiar to Gothic architecture. Small window openings were often filled with coloured glass in early Christian times. But the production of intricate designs, including rich patterns and figures, and the elaboration of them with details drawn with a pencil and afterwards burnt in, began in the Romanesque period, and was perfected in the early Gothic.
The inherent limitations of this art are indeed of such a nature as to confine its development within narrow lines. The material resources of the artist were limited to sheets of glass variously coloured while in a molten state by the use of metallic oxides. These sheets were cut up into the required shapes, and the pieces were fitted together, mosaic-fashion, to form the main design, while this patchwork of colour was supplemented by the very simplest delineation and rudest modelling by means of a pencil charged with a neutral pigment. It is plain that only a most conventional kind of art could be produced by such means. Yet with these materials the mediæval artist was able to work without embarrassment, and in the many examples of his skill which still remain we may see that he was no less unerring in his judgment, and constant in his obedience to the principles involved, than were, in their respective departments, the stonemasons and the sculptors.
The task of the designer in stained glass was, on the one hand, to subdue the light and give a comfortable sense of enclosure, and, on the other, to produce brilliant harmonies of translucent colours, and to add such pictorial interest as the conditions controlling his art would permit. The fundamental difference between this art and the art of wall painting is, of course, that in the one case light passes through the design everywhere, while in the other it falls upon its surface only. This difference separates the two arts by an impassable gulf. With wholly transparent media those scenic effects, which are dependent upon a greater or less development of light and shade, are impossible. In all arts the true designers willingly submit to the limitations which the nature of their materials imposes, and in no art
