This particular medal is from the Smithsonian's collection, and was awarded to Sergeant Major Christian A. Fleetwood of the 4th U.S. Colored Troops in 1865.
(Division of the History of Technology, Armed Forces History, National Museum of American History, Smithsonian Institution)
The original design of the army Medal of Honor shows the goddess Minerva fending off a symbol of discord. The thirty-four stars surrounding the figures represent the number of states in the Union. (NARA, Records of the Adjutant General's Office, 1780-1917, RG 94)
The Medal of Honor was the first medal for which all enlisted men in the U.S. military could be nominated. A bill introduced by the junior senator from Massachusetts, Henry Wilson, on February 17, 1862, calling for the introduction of an army Medal of Honor, was fashioned after a navy medal bill signed by the President two months earlier. On July 12, 1862, Lincoln signed Wilson's bill into law, which called upon the President to present the Medal of Honor "in the name of Congress to such noncommissioned officers and privates as shall most distinguish themselves by their gallantry in action and other soldier like qualities during the present insurrection."
On March 3, 1863, Lincoln signed a measure broadening the President's authority to award the army Medal of Honor to "such officers, noncommissioned officers and privates as have most distinguished, or who may thereafter most distinguish, themselves in action."
[Excerpted from "The Army Medal of Honor: The First Fifty-five Years" by Mark C. Mollan in Prologue, the Journal of the Archives (NARA), Summer 2001, Vol. 33, No. 2 ]