The destruction of opium at Humen began on 3 June 1839 and involved the destruction of 1,000 long tons (1,016 t) of illegal opium seized from British traders under the aegis of Lin Zexu, an Imperial Commissioner of Qing China. Conducted on the banks of the Pearl River outside Humen Town, Dongguan, China, the action provided casus belli for Great Britain to declare war on Qing China. What followed is now known as the First Opium War (1839–1842), a conflict that initiated China's opening for trade with foreign nations under a series of treaties with the western powers.