In June 1900, the Boxer Rebellion broke out in China. Colonel Chaffee was sent to China in July as the commander of the U.S. Army's China Relief Expedition. The Expedition was a part of the international force sent to rescue Western citizens and put down the rebellion. Chaffee participated in the Gaselee Expedition and subsequently the Battle of Peking, in which the legations were relieved. In 1900-1901 American forces were included in the Allied occupation of Peking (Beijing). As American commander Chaffee began public health, relief, and police operations in cooperation with Chinese officials. Chaffee concluded that Asiatics respected only the superior power. Reassigned to the Philippines he applied the lessons there, combining benevolence and public health measures with force and cooperation with local officials.