1866 On December 21, 1866, a battle occurred between Sioux, Cheyenne, and Arapahoe warriors and a force commanded by Bvt. Lt. Col. William J. Fetterman. Fetterman and all the men under his command were killed at what became known as Massacre Hill near Fort Phil Kearny. The battle is known as both the Fetterman Massacre and The Battle of The Hundred Slain, part of Red Cloud's War. When Fort Fetterman was established in 1867, it was named for the Lieutenant Colonel.