EARLY CrunsTIAN, BYZANTINE, AND MOHAM MEDAN. The development of the basilical church involved the general use of windows, and many more actual example4 have remained of this period, though they arc far from being as beautiful as those of the Roman Empire. The normal brick window of Early Christian and Early Byzantine buildings was a single, plain and rather wide round-arched opening, without moldings or sculpture. Only in the East, where stone was commonly used, was the old Gr:vco Roman 'skinless partly perpetuated, especially in the ruined cities of Central Syria, where hun dreds, not to say thousands of windows reinain in religious and secular structures built during the third, fourth, fifth, and sixth centuries A.D.
As the Middle Ages approached the Byzantine windows took on new forms, and \\sere slenderer, often with two lights, separated by marble colon nettes and framed with moldings. The Roman custom of filling the aperture with glass or transparent marble was continued and many examples remain of the perforated marble slabs; usually the perforations were small and circular, quite often square, sometimes in elaborate pat terns. The perforations were at times filled with colored glass, thus combining the two varie ties. The churches of Grado, Parenzo, Ravenna, Rome, etc., retain examples dating from the sixth to the eleventh century. In the Mohammedan East windows were early provided with ?unshorn biycli, lattice-work and stucco window sashes cut out in free and exquisite floral designs, filled with stained glass; this was practiced especially in Egypt (Cairo), but perhaps also in Syria, and many beautiful examples are to be seen in the mosques of Constantinople.
MEDLEvAL. Romanesque windows are ordi narily single, round-headed apertures, splayed where the wall is thick; very seldom does a two light window with central colonnette occur. Oc casionally the arched opening was framed with carving or treated, like the superb doorways, with receding arches and carved moldings, es pecially in Southern France and Southern But the highest development of the window came with the Gothic style. Its perfect system of bal anced construction permitted the opening of win dows as vast as the entire space between the supporting piers of a vaulted interior. Thus arose the magnificent pointed and circular win dows with tracery (q.v.), dividing them into several narrow lights. They were filled with stained glass. which developed into an impor tant brunch of painting. For the first time—ex cept for a few late Romanesque examples in France and Germany—the pieces of stained glass framed in lead were so assembled as to form immense figured compositions rivaling wall paintings. France led the way. closely followed in this art by England and Germany. Italy was least important.