Mark with US Army Shoulder Sleeve Insignia: 56th | #400579

The United States Army is one of the three military departments (Army, Navy and Air Force) which reports to the Department of Defense. The modern US Army has its roots in the Continental Army, which was formed on 14 June 1775. Field artillery is a category of mobile artillery used to support armies in the field. A shoulder sleeve insignia (SSI), is an embroidered patch worn on some uniforms of the United States Army. The SSI in this image was approved for the 56th Field Artillery Command in 1971.