The First Opium War between China and Britain took place between 1839 and 1842. The war was fought primarily to secure trade rights for British merchants in China, though it ultimately marked the start of a period of Western imperialism in China.
The war began after the Chinese government ordered the seizure of large amounts of opium imported by British merchants. This seizure outraged many in Britain, who believed that their merchants had the right to sell opium in China, and they launched a campaign to convince the British government to take action against the Chinese. In 1839, the British sent a diplomatic mission led by Lord Palmerston to Beijing to demand that the Chinese government repeal its anti-opium laws and open its ports fully to British ships. When the Chinese refused, the British declared war, thus initiating the First Opium War.
The first military encounter of the war occurred in 1840, when British forces attacked and occupied the port of Dinghai on the Chinese coast. This was followed by further battles in which the British gained the advantage, aided by their superior weapons and tactics. After several months of fighting, the Chinese signed the Treaty of Nanking in 1842, ending the war and giving the British control of several important Chinese ports, including Canton and Shanghai.
The war had a profound impact on modern China. It caused an immense loss of life and resources, as well as a severe humiliation of the Chinese people and government. It also opened China’s ports to foreign trade, paving the way for the British and other Western nations to gain greater access to and influence over Chinese markets. This set off a period of colonialism and oppression of the Chinese people that would last for decades.