Up to the close of the seventeenth century, when China was more or less self-contained, banking was necessarily restricted in its scope. Owing to the situation arising out of the chaos of currency, a greater part of the business of the small banks consisted simply in changing one set of coins into another, without reference to trade or any other factors which have made banking in modern times a business of extreme importance. The principal business of the banks was the changing of one set of money into another; but it must be understood that in those times silk, cowrie shells and even rice performed as important a function as a sovereign or a franc does to-day. These articles were usually accepted not only by the Government in lieu of taxation, but also in general business transactions. Although there was a small volume of inter-provincial trade even as early as the fifteenth or sixteenth century, the trade was practically confined to very narrow limits. The village, the town or the province were all self-contained; at least their efforts were all directed towards supplying their wants without any outside agency. Thus the banks performed a very minor part, but every district or every province had to send money and tribute to the capital; a district of a province had to make arrangements to send its quota to the provincial capital, and the authorities in the latter had to make arrangements to dispatch their dues to Peking. As taxes were collected in kind, and as a portion of the commodities received had to be converted into articles of light weight before being dispatched to Peking the necessity of an agent to help towards the despatch of money and articles to Peking was acutely felt. The Shansi bankers, who have a very interesting history, undertook to do this as early as a.d. 900.