Event of 1839: Destruction of opium at Humen begins, casus belli for Britain to open the 3-year

Background. Opium had been illegal in China since 1800, yet private traders smuggled consignments from Calcutta to southern ports. By 1838, Chinese opium addiction had grown to between four and twelve million people. The Qing government, having vacillated on its approach, decided to expel merchants involved in the illegal trade, setting the stage for Lin Zexu's intervention.

Enforcement. On 18 March 1839, Lin Zexu summoned the twelve Chinese merchants of the Cohong who acted as intermediaries for the foreign opium traders. Charles Elliot ordered British ships to leave Canton for Hong Kong safety before arriving at foreign factories on 24 March, three days after Lin's deadline expired. By 21 May, 20,283 chests of opium had been unloaded at Chuanbi.

Aftermath. The destruction provided casus belli for Great Britain to declare war on Qing China. William Jardine believed open warfare was necessary to force compensation and began a campaign in London to sway the British government. In spring 1840, an expeditionary force left India for China, leading to the First Opium War.