Tientsin, 13 July 1900. The so-called "Boxers" were fanatical members of a Chinese secret society who wished to drive all foreigners from China and eradicate foreign influences. The Boxer movement gained momentum in the final years of the nineteenth century. By early June of 1900 the foreigners in China, especially those in Peking, found themselves in grave danger.
An international column of sailors and marines, including 112 Americans, made a hurried attempt to go to the relief of Peking, but met with severe resistance after it left Tientsin and failed to get through (10-26 June). The movement against Westerners in Peking reached a climax on 20 June 1900 when the German minister was murdered. About 3,500 foreigners and Chinese Christians, fearing for their safety, took refuge in the foreign legation compound, where they were besieged by thousands of Chinese. A composite military force of 407 men (including 56 Americans) plus about 200 civilians defended the compound. The Great Powers took immediate steps to organize a large relief expedition for Peking, to stamp out what came to be known as the Boxer Rebellion.
Using Manila as a main base, the United States promptly dispatched to China Regulars intended for use in the Philippine Insurrection. The 9th Infantry and a Marine battalion landed at Taku on 7 July 1900. Two battalions of the 9th joined contingents of other powers in an attack on Tientsin, which fell on 13 July, the Americans suffering 95 casualties.
Yang-tsun, 6 August 1900 and Peking, 14-15 August 1900. On 4 August 1900 an allied force of eighteen or nineteen thousand men began an advance on Peking, 70 miles distant. The American contingent, some 2,500 men under Maj. Gen. Adna R. Chaffee, consisted of the 9th Infantry and 14th Infantry, elements of the 6th Cavalry, the 5th Artillery, and a Marine battalion. High points of the fighting en route were at Pei-tsang, which fell on 5 August 1900, and a severe engagement for American and British contingents at Yang-tsun on 6 August. In the seizure of the Outer City of Peking on 14 August, elements of the 14th Infantry scaled the Tartar Wall, planted the first foreign flag ever to fly there, and opened the way for British units to relieve the legation compound. On the following day "Reilly's Battery" (Capt. Henry J. Reilly's Light Battery F, 5th Artillery) blasted open the gates on the American front in the assault on the Inner City.
Most American units were withdrawn to Manila before winter, and mopping up operations in the provinces were left to the other Powers. A few American Regulars remained to form part of an allied occupation force and a small guard for the United States Legation in Peking.
The Boxer Protocol of 7 September 1901, negotiated by the Great Powers with China, included provisions for a fortified legation quarter, foreign garrisons along the Tientsin-Peking railway, and a large indemnity. In 1908 the United States remitted a portion of its share of the indemnity, which the Chinese Government diverted to educational purposes.