The opium wars are conflicts motivated by commercial reasons which opposed China of the Qing dynasty, wanting to prohibit the opium trade on its territory, to several Western countries, wanting to continue it, in the 19th century.
The First Opium War was fought from 1839 to 1842 and pitted China against the United Kingdom.
The Second Opium War was fought from 1856 to 1860 and this time saw the intervention by France, the United States and Russia alongside the United Kingdom. The name by which this war is designated is explained insofar as it can be considered as an extension of the first Opium War.
The conflict arose from tensions caused by the Qing government's tightening of anti-opium laws, as the British attempted to export opium from British India to China.
China lost both wars, and was forced to allow the opium trade financed by a world famous bank, even today, and to sign unequal treaties, resulting in the opening of certain ports and the legacy of Hong Kong to Britain. Several other Western countries took the opportunity to sign unequal treaties with China, thus forcing its opening to trade. Foreign influence resulted in the Boxer Rebellion (1899-1901), and the fall of the Qing dynasty (1911).