Jia Dan - Written Works

Written Works

In the 40-volume work that Jia completed in 801, Jia wrote of two common sea trade routes in his day: one from the coast of the Bohai Sea towards Silla in Korea and another from Guangzhou through Malacca towards the Nicobar Islands, Sri Lanka and India, the eastern and northern shores of the Arabian Sea to the Euphrates River. Indeed, Korean vessels dominated the Yellow Sea trade, while most Japanese vessels were forced to venture towards the mouth of the Huai River and Yellow River, and even as far south as Hangzhou Bay. Jia wrote that the ships in the Euphrates had to anchor at the mouth of the Euphrates and transfer the trade goods on land towards the capital (Baghdad) of Dashi Guo (Abbasid). This was confirmed by the contemporary Arab merchant Shulama, who noted that the draft in Chinese junk ships were too deep to enter the Euphrates, forcing them to land passengers and cargo ashore on smaller boats. A small branch of this extensive second trade route led all the way to Dar es Salaam in Tanzania, East Africa. In his work written between 785 and 805, he described the sea route going into the mouth of the Persian Gulf, and that the medieval Iranians (whom he called the people of Luo-He-Yi) had erected 'ornamental pillars' in the sea that acted as lighthouse beacons for ships that might go astray. Confirming Jia's reports about lighthouses in the Persian Gulf, Arabic writers a century after Jia wrote of the same structures, writers such as al-Mas'udi and al-Muqaddasi.