At around the end of 2nd century BC , the most edacious foreign consumer of Chinese silk was Parthia of Iran. In about 105 BC Parthia and China created a bilateral trade route between them which marks the birth of the silk road. The silk road was not one single road, but many caravan tracks that trailed through some of the toughest areas including the highest mountains and the harshest deserts on earth.
Ch'ang-an (modern Xian) was the starting point of the rout. Westward, the main artery of this trade route divided at Dunhuang. One branch headed north just above the harsh Taklamakan desert ( a place where no one gets out alive) going through Turfan, kucha, and Aksu. At the same time the other branch headed south to Khotan and Yarkand. Finally, the two roads met in Kashgar where the caravaners readied themselves for the harsh and long treck through some of the highest mountains on earth. The trail headed west and attempted to cross a series of passes through the Pamiers and the Tian Shan mountain ranges. Once over the mountains, the road headed west through Ferghana Valley to Kokand, Samarkand, and Merv, and finally to Iran and Constantinople. When the caravans reached the Black and the Mediterranean seas and goods were exchanged and the long march back began over the same tracks. Many arteries forked off from the main route. Some major ones headed south to India over the Karakoram range. Still others, headed north through the Ili river and across the Saka steppes.
Caravaners did not usually travel all the way from Ch'ang-an to the west, or vice versa. They usually traveled short distances along certain paths and traded goods according to the needs and demands of that area.
Wars, robbers, and natural disasters were expected at any given time. Bandits from Tibet, Mongolia, and the state of Hunza in Karakoram added to the dangers of these expeditions. One of the most powerful of these groups was the nomadic Mongolian alliance Xiong-nu. At the same time, the Han emperors tried to secure the road by spending much of their resources and policing much of the route.
Caravans headed west with silk, porcelain, spices, gems, perfumes, teas, and seeds of orange, peach and other trees. From the west they brought back gold, silver, ivory, jade and other precious stones, wool, Mediterranean colored glass, grapes and wine and European delicacies such as figs and walnuts, plus acrobats and ostriches. The middle part of the path was central Asia which contributed its native beasts, horses and two humped camels.
Going in both directions, aside from silk and other goods, were new ideas and technologies and intermixing of different cultures and religious beliefs. Many different religions all coexisted along this road, some were Manichaeism, Zoroastrianism, Buddhism, Nestorian Christianity, Judaism, Confucianism, Taoism, and Sufism of grassland nomads.