Since the Egyptians, craftsmen have been learning more about making glass, and new ways to shape it into beautiful and useful objects. The first things that the Egyptians made were little beads and amulets which were charms to ward off evil spirits. By 1500BC, they had made small glass jars by winding threads of melted glass around a core of clay and sand. The core would then be crumbled and removed as soon as the glass had set. The next discovery in the story of glass was made by the Syrians who used a method known as glass blowing, or shaping hot glass. Once this was known, all sorts of new shapes could be made. From about AD200, the different styles came together and all parts of the Roman Empire began to make glass of the same kind. Glass was used more generally then than it ever was again until the 19th century. Thousands of bottles were made to hold oil, wine and other liquids, and were often square to be convenient for storage. Later in the 5th century, the Roman empire fell, and the glass industry was scattered. In the east of the old empire, glass was still made but only for luxury use. In Northern Europe throughout the middle ages, small glass factories worked deep in the forests, which supplied timber for the furnaces. From these workshops came the glass for church windows, and craftsmen in the 12th century learned to colour glass to be used in the making of patterned windows. The secret of making colourless glass had been lost in Europe, but by the 15th century, glassmakers in Venice had rediscovered it and named it Cristallico because it looked like the natural stone, rock crystal. The Venetians also knew how to colour glass, among the highly prized objects at the time were stately goblets, bowls and large jars and ewers. Italian glassmakers travelled through Europe taking their craft with them, so that by the 17th century, their glass was made alongside the less popular green country glass. By the end of the 17th century, Venetian glass had lost favour amid the demand for a more solid glass. To satisfy this demand, English and German glassmakers were successful. The Germans made a thick glass suitable for wheel engraving - the Venetian glass had been too thin and fragile for this. The English also produced a glass which was heavy and brilliant in appearance. In 1745 a tax was put on glass according to its weight so lighter glasses were made.