Why Was the Extraterritoriality Created?

In 1858, after Commodore Matthew Perry's fleet forced Japan to open several ports to ships from the United States, western powers rushed to established "most favored nation" status with Japan, which included extraterritoriality.

What did extraterritoriality do?

In international law, extraterritoriality is the state of being exempted from the jurisdiction of local law, usually as the result of diplomatic negotiations. ... Extraterritoriality can also be applied to physical places, such as foreign embassies, military bases of foreign countries, or offices of the United Nations.

When was extraterritoriality created?

In 1844 the United States gained the right of extraterritoriality in China (see Cushing's Treaty). The United States expanded its jurisdiction in 1863, by forming the International Settlement in Shanghai in cooperation with Great Britain.