Most of the jewels shipped from Rome to China came from Egypt, the Mediterranean Sea and the Red Sea. Take coral as an example. According to ancient western documents, as early as the early years of AD, coral became an important export of the Roman Empire to India. There are many such records in China's historical records. For example, there are words such as "Coral is in Daqin", "Coral is in the West Sea of Daqin" and "Coral is in Daqin, and the continent is rising in the sea". The Red Sea is also called "Coral Sea" because it is rich in corals. In these China history books, people in the Mediterranean and the Red Sea have also described in detail how to collect corals with iron nets.