The British legally forced the Qing dynasty to stop using the Chinese character yi , to refer to them in official documents. This was a minor goal of the 2nd Opium war and was agreed to as part of the 1858 Treaty of Tientsin.
Article 51 of the treaty explicitly stated that the character *yi* would no longer be applied to the government or subjects of the British Queen, in any official Chinese documents issued in the capital or the provinces. #history