Threatened by the "Boxers", who were supported by regular Chinese troops, 900 soldiers and civilians from Europe, Japan and the United States, and about 2,800 Chinese Christians took refuge in the Beijing Legation Quarter. The ensuing siege lasted 55 days and was broken by an international military force, which went on to occupy Beijing. "Pekin Castle" refers to the imperial palace, shown here under attack from Japanese and British forces.
Torajirō Kasai, The fall of the Pekin castle, the hostile army being beaten away from the imperial castle by the allied armies, chromolithograph, 45.8 x 63.7 cm, 1900; source: Library of Congress, series: Boxer Rebellion picture series, No. 21, http://www.loc.gov/pictures/item/2009631627/, public domain.