![[Media/Silkworms3000px.jpg]] *Silkworms eating mulberry leaves. China was able to keep this secret for millennia.* The earliest known use of silk is dated to about 5,600 years ago in the Yangtze River Valley. Silk, the thread spun from the cocoons of the *Bombyx mori* silkworm, became a hallmark of Chinese culture. Wild silkworms, which were abundant in the region, were fed on mulberry leaves and then their cocoons were harvested and boiled to extract silk threads. The existence of the silkworm, its exclusive diet of mulberry leaves, and the production process were all closely-guarded secrets of Chinese culture and later the Chinese Empire, which managed to protect the secret for about 4,000 years. Silk production was a state-controlled industry and there were severe penalties including execution for leaking information about the process. Finally, through a combination of migration and espionage, the secret of silk eventually spread to Korea and Japan, and then along the Silk Road in the first century of the common era. Sericulture reached India around 300 CE and Byzantium by 552. While China held the secret, silk was one of the most sought-after products of the ancient world; worth its weight in gold in imperial Rome. Silk production and trade was a key to China's wealth, cultural prestige, and diplomatic power, accounting for possibly a quarter of China's income at the peak of Silk Road exports. ![[Media/Bombyx_mori_Cocon_02.jpg]] *Silk cocoon.* ----- Next: [[3.16 - City-States, Empires]] Back: [[3.14 - Textiles]]