During the period of the style known as Decorated Gothic, furniture was framed and panelled, and the details closely resembled those used in architectural decoration in stone. [Illustration: No. 67. Decorated Gothic Spire, Whittlesea.] The general effect of Decorated is a tendency to horizontal banding, in contrast to the vertical effect of the earlier period, to which eventually the later Perpendicular reverted. _Perpendicular Gothic_ In the succeeding phase the Triforium which had gradually become less important, entirely disappeared and the clerestory windows enlarged, to the extent that this part of the structure became merely a frame for the increased glass areas. It will be apparent from the foregoing that whereas in the early churches of the Romanesque period the interior effect was mysterious owing to inadequate openings for light, the later and growing tendency was to increase the lighting capacity by enlarging the windows of the clerestory. _Glass Windows_ Doubtless the development in the size of windows was due to some extent to the growing use of glass, which, though rare, was employed during the later Romanesque through Byzantine tradition. [Illustration: No. 68. Perpendicular Gothic Bay shewing development of Clerestory.] These early windows were geometric in design, consisting of medallions, oval, circular or quatrefoil in shape, containing figure subjects set in a diapered background, the whole being executed in small pieces of coloured glass united by lead framings. While the windows were single openings, this form of glazing necessarily restricted the size, though more adequate lighting was achieved by grouping two or more windows together. With the development of tracery the technical difficulties were to some extent overcome; a window divided into comparatively small compartments could be more easily glazed than single openings of large size; thus glazed windows of greater dimensions were rendered possible. [Illustration: No. 69. Perpendicular Gothic Windows. A. Aylsham Church, Norfolk. B. King’s College Chapel, Cambridge.] In the Decorated windows the lower lights were devoted to the subject, which in many instances was carried through the area, regardless of the dividing bars or mullions. In the Perpendicular each light or opening had usually its own subject or figure, surmounted by canopies, the upper spaces formed by intersection of the tracery bars were occupied by various details suitable to the different shapes. The Arch of the Perpendicular style is materially different, being composed of elliptic curves struck from four centres. Mouldings became even more shallow in section, and the tracery less florid than formerly, though extremely rich in appearance when used in the profusion that developed in the fan vaulting of this period. [Illustration: No. 70. Perpendicular Gothic Fan Vaulting. St. Mary, Aldermary.]