Stained glass is translucent colored class set in a lead framework, and usually used in windows. Stained glass was used in Early Christian and Byzantine churches as well, but was particularly favored by Gothic architects for whom it began an important form of art. The process of making stained glass hasn’t changed much in nearly a thousand years. The colors in the glass come from adding metal oxides to molten glass, a labor-intensive process. Detailed images are made by using black enamel paint and fusing it to the glass through firing. The glass artist then organizes the colored glass fragments on a flat surface, like an enormous puzzle, until reaching the desired image, and then joins the glass to lead strips and iron bands, which support the heavy glass.