History saw the decline of Glassmaking skills in Europe from 200 AD through 1200 AD. The standards, the range of articles, and the quality of the material remained far below that of Roman glass standards. Bubbles and streaks marred the glass, and stained-glass windows appeared in the new Gothic churches in Europe beginning in the 12th century. These beautiful glass windows reached full brilliance during the 13th and 14th centuries. Fusing stains to the surface of the glass produced the most colors while achieving clear, colorless glass continued to be a very difficult task. This proved disappointing to glass workers of that time period