In the beginning of the Middle Ages, silk in Europe was known only as the expensive fabric imported from Asia. But by the end of The Middle Ages, silk had become one of Europe's major industries. How did this change occur?
Before the 500’s, the Chinese and Persians held a monopoly over silk manufacture and sale, obtaining fabulously high prices in Roman and, later, Byzantine markets.
In 550, Byzantine emperor Justinian I sent two monks on a secret mission to China to bring the precious little silkworms back to Constantinople. After a dangerous journey, the two monks successfully smuggled silkworm eggs out of China and brought them back to Constantinople.
From there, the raising of silkworms and the manufacture of silk spread throughout the Mediterranean world, particularly to Moorish Spain. By the 1200s, Italy and Sicily had become the center of silk manufacturing in Western Europe. By the end of the 1400s, the French rivaled the Italians and Sicilians in the manufacture of silk. Silk weaving also became one of the skills of the Flemish manufacturers, and the silk trade spread to England with the wool industry in the late 1500s.