The Jurchens, the ancestors of the Qing Manchus, had lived scattered in Manchuria and had made their living mostly on ginseng gathering and animal hunting. Their residential areas, rich with deep forest and numerous rivers, provided great habitation for all kinds of flora and fauna, but not so proper for agriculture. Based on their activities of foraging and hunting, the Jurchens developed a unique social organization that was later transformed into the Banner System, the most distinctive Qing military institution. By the sixteenth century, that the external trade brought considerable changes to Jurchen society. A huge amount of foreign silver, imported from Japan and South America to China, first invigorated commercial economy in China proper, and later caused a huge influence on Ming frontier regions, including Manchuria. In the late sixteenth century when the tradition of foraging and hunting encountered with silver economy, the Jurchen tribes became unified after years of competition and transformed themselves into the Manchus to build the Qing empire in 1636. In 1644 the Manchus succeeded in conquering the China Proper and moved into Beijing. Even after that, the Manchu imperial court never forgot the value of Manchurii ginseng; instead, they paid great efforts to monopolize this profitable root. Until the late seventeenth century, the Qing court used the Banner System to manage Manchurian ginseng. The banner soldiers stationed in Manchuria checked unauthorized civilian entrances in this frontier and protected its ginseng producing mountains from the Han Chinese people. All the process of ginseng gathering was managed by the institutions under the direct control of the imperial court, such as the Imperial Household Department, the Butha Ula Office, and the Three Upper Banner in Shengjing. Banner soldiers were dispatched to the given mountains, collect the given amount of ginseng, and send them to the imperial court in Beijing. The state monopoly of ginseng was maintained throughout the eighteenth and nineteenth centuries under the principle that Manchuria and its natural resources should be guarded from civilian encroachment. At the same time, Manchurian ginseng was considered as an important source of state revenue. The imperial court and financial bureau wanted to collect ginseng as much as they needed. By the late seventeenth century as the ginseng management by the banner soldiers failed in securing the ginseng tax, the Qing court began to invite civil merchants to ginseng business. During the eighteenth century the Qing ginseng policy became more dependent on civil merchants, both their money and management. In 1853 the Qing finally ended the ginseng monopoly, but it was before the early eighteenth century that wealthy merchants hired ginseng gatherers and paid ginseng tax to the state. The Qing monopoly of ginseng was in fact maintained by the active participation of civil merchants in the ginseng business.