Two thousand years ago, at the time of the Roman emperor, Augustus, the two words CHINA and SILK meant one and the same thing. Something Chinese was Serie, a word derived from Ser, a Chinese word for silkworm. Sericulture, or silkworm breeding was a skill practised only by Chinese. The story of silkworms began in China four thousand six hundred years ago, in the reign of the Empress Xi Lin Shi, who taught her people the art of raising the silkworm. Xi Lin Shi later came to be worshipped as a goddess. The silkworm moth, Dombyx mori, is the only moth exploited by man. It is a moth which, after thousands of years in captivity, has lost its ability to fly. The caterpillar feeds on mulberry leaves, and with this diet it grows from an initial tree or four millimeters in length to eight or nine centimeters in maturity. When it reaches this size, the caterpillar begins to make its cocoon, from which we eventually get our silk. The silk is unwound from the cocoon in one very long thread: from three hundred meters to over a kilometer in length. Wool, flax, cotton, hemp and silk are natural fibre textiles. They are the oldest of all cloths, and of all of them, silk is still the most precious.