rose window, also called wheel window, in Gothic architecture, decorated circular window, often glazed with stained glass. Scattered examples of decorated circular windows existed in the Romanesque period (Santa Maria in Pomposa, Italy, 10th century). Only toward the middle of the 12th century, however, did the idea appear of making a rich decorative motif out of a round window. At this time the simple rose window became a distinguishing characteristic of many transitional and early Gothic churches. It was used mainly at the west end of the nave and the ends of the transepts. The introduction of developed bar tracery