After graduating from Yale with a degree in engineering, Sterling Clark (1877–1956) was commissioned a second lieutenant in the Ninth Infantry Regiment of the U.S. Army. He served in the Philippines for six months before being mobilized to China in the summer of 1900 as part of the China Relief Expedition, an international force protecting Western interests threatened by the Boxer Rebellion—the militant Chinese nationalist movement opposed to the strong influence of Western powers and Japan. He fought in that conflict’s major engagement, the Battle of Tientsin [Tianjin], participated in the rescue of the foreign settlement in that city, and led his company as part of the official guard of the American-controlled zone in Beijing.

Clark spent nearly half his army service in China and the remainder at the War Department in Washington, D.C., where he researched and analyzed the military capabilities of the great world powers. While in the United States between his two tours of duty in China, Clark spent time reading accounts of other expeditions in Asia, seeking out a copy of William Woodville Rockhill’s Diary of a Journey through Mongolia and Thibet in 1891 and 1892 and E. Huc’s Travels in Tartary, Thibet, and China: During the Years 1844–1846. Clark’s army years provided his first exposure to Asia, and the experiences and knowledge that he gained there inspired his decision to mount his expedition to China.