In 221 BCE, tea was first used for ceremonial purposes in ancient China. It is known that by 1000 BCE, there were already tea farms. By the Song Dynasty period, tea was a major export. Through the Silk Road, tea spread to Arab countries and Africa. From the second century BC to the end of the fourteenth century AD, a great trade route originated from Chang'an (now Xian) in the east and ended at the Mediterranean in the west, linking China with the Roman Empire. This ancient route not only circulated goods, but also exchanged the splendid cultures of China, India, Persia, Arabia, Greek and Rome