Fort Sill was staked out in 1869 by Major Philip Sheridan as part of a campaign into the Indian Territory to stop raids on settlements over the borders of Texas and Kansas. At the beginning of the Twentieth Century it seemed that the post would be abandoned following the demise of other U.S. Army forts in Oklahoma. With the disappearance of the frontier, the mission of Fort Sill gradually changed from cavalry to field artillery. Fort Sill has the distinction of being a National Historic Landmark and is home to the Fort Sill Field Artillery School and Army Air Defense Artillery School. Fort Sill, Oklahoma is literally the Wild West come to life through its historic buildings, museum and sites such as Geronimo’s grave.