The Anglo-Chinese War, also known as the Opium War or the First Opium War, was a series of military engagements fought between Britain and the Qing dynasty between 1839 and 1842. The immediate issue was the Chinese seizure of private opium stocks at Canton to stop the banned opium trade, and threatening the death penalty for future offenders. The British government insisted on the principles of free trade, equal diplomatic recognition among nations, and backed the merchants' demands. The British navy defeated the Chinese using technologically superior ships and weapons, and the British then imposed a treaty that granted territory to Britain and opened trade with China. Twentieth century nationalists considered 1839 the start of a century of humiliation, and many historians considered it the beginning of modern Chinese history.