July 1937: Marco Polo Bridge Incident, outbreak of (Second) Sino-Japanese War
August: Formation of the Shanghai Expeditionary Army
1899: Representatives of 26 nations met for the International Peace Conference where they drafted the Convention with Respect to the Laws and Customs of War on Land, one of the first formal statements of international laws related to war and war crimes.
First Opium (First Anglo-Chinese) War. Treaty of Nanking signed (1842) ending the First Opium War. China to pay large indemnity and extraterritoriality and most favored nation principle established in China