<P> Critics, however, focused on the immorality of opium . William Ewart Gladstone denounced the war as "unjust and iniquitous" and criticised Lord Palmerston's willingness "to protect an infamous contraband traffic ." </P> <P> The war marked the start of what 20th century Chinese nationalists called the "Century of Humiliation". The ease with which the British forces defeated the numerically superior Chinese armies damaged the Qing dynasty's prestige . The Treaty of Nanking was a step to opening the lucrative Chinese market to global commerce and the opium trade . The interpretation of the war, which was long the standard in the People's Republic of China, was summarized in 1976: The Opium War, "in which the Chinese people fought against British aggression, marked the beginning of modern Chinese history and the start of the Chinese people's bourgeois - democratic revolution against imperialism and feudalism ." </P> <P> The Treaty of Nanking, the Supplementary Treaty of the Bogue, and two French and American agreements were all "unequal treaties" signed between 1842 and 1844 . The terms of these treaties undermined China's traditional mechanisms of foreign relations and methods of controlled trade . Five ports were opened for trade, gunboats, and foreign residence: Guangzhou, Xiamen, Fuzhou, Ningbo, and Shanghai . Hong Kong was seized by the British to become a free and open port . Tariffs were abolished thus preventing the Chinese from raising future duties to protect domestic industries and extraterritorial practices exempted Westerners from Chinese law . This made them subject to their own civil and criminal laws of their home country . Most importantly, the opium problem was never addressed and after the treaty was signed opium addiction doubled . China was forced to pay 21 million silver taels as an indemnity, which was used to pay compensation for the traders' opium destroyed by Commissioner Lin . A couple of years after the treaties were signed internal rebellion began to threaten foreign trade . Due to the Qing government's inability to control collection of taxes on imported goods, the British government convinced the Manchu court to allow Westerners to partake in government official affairs . By the 1850s the Chinese Maritime Customs Service, one of the most important bureaucracies in the Manchu Government, was partially staffed and managed by Western Foreigners . In 1858 opium was legalised, and would remain a problem . </P> <P> Commissioner Lin, often referred to as "Lin the Clear Sky" for his moral probity, was made a scapegoat . He was blamed for ultimately failing to stem the tide of opium imports and usage as well as for provoking an unwinnable war through his rigidity and lack of understanding of the changing world . Nevertheless, as the Chinese nation formed in the 20th century, Lin became viewed as a hero, and has been immortalized at various locations around China . </P>

What commodity ultimately led to british gaining control of hong kong in the treaty of nanjing