Commercial treaty till the middle of the century, apparently with irresistible support, they suddenly collapsed under the strain of a season of exceptionally short crops. Both their continued maintenance and their final sudden abolition are in some respects divergent from the general course of British tariff history. Commercial treaty A commercial treaty is a formal agreement between states for the purpose of establishing mutual rights and regulating conditions of trade. It is a bilateral act whereby definite arrangements are entered into by each contracting party towards the other—not mere concessions. For example, the Methuen Treaty was a commercial treaty between Portugal and
Unequal treaty Great Britain, Guangzhouwan to France, Taiwan to Japan, the Jiaozhou Bay concession to the German Empire and concession territory in Tientsin, Shamian, Hankou, Shanghai etc.), and make various other concessions of sovereignty to foreign "spheres of influence", following military threats. The earliest treaty later referred to as "unequal" was the 1841 Convention of Chuenpi negotiations during the First Opium War. The first treaty between China and Great Britain termed "unequal" was the Treaty of Nanjing in 1842. Following Qing China's defeat, treaties with Britain opened up five ports to foreign trade, while also allowing foreign missionaries, at least in theory,