St. John, Devizes, c. A.D. 1160.
The fine circular windows with wheel-like divisions belong to this period: Barfreston, in Kent, is a good example. St. James, Bristol, is a singular one, the effect of which is rich and good. There was frequently one in the centre of the west front, which was called the oculus, or eye of the building. These large round windows are much more common on the Continent than in England. In Italy there are many fine examples, as at Toscanella, Perugia, and Assisi. The French also appear to have always had a particular fondness for this kind of window, which in the later styles becomes the magnificent rose-window, so often the glory of the French churches.
St. James, Bristol.
Norman windows are far less common than the doorways, having frequently been destroyed to make room for those of later styles; probably for the purpose of introducing the painted glass of those periods, which did not suit well with the early windows. Small circular openings are also a common feature, as in the clerestory of Southwell Minster. The zigzag molding is frequently used in the arches of windows, as at St. John’s, Devizes, p. 44; occasionally, but not so frequently, this ornament is also carried down the jambs, as at Iffley. Windows of two lights divided by a mullion were not introduced until after the Norman period. The walls being generally very thick, the opening is small and narrow on the outside of the wall, and is very widely splayed to admit more light; so that while the glass is less than a foot wide, the opening of the splay on the inner side of the wall is three feet wide.
Iffley, Oxon, c. A.D. 1166.