The traditional War Office seal used since the Revolution was designated as the Department of the Army Seal by the National Security Act of 1947. The date “MDCCLXXVIII” and the designation “War Office” are from the seal. The date (1778) refers to the year of its adoption. The term “Board of War and Ordnance, United States of America” was used during the Revolution, later shortened to “United States of America, War Office” and was always associated with the Headquarters of the Army since the Navy had its own seal.
The center of the seal is a Roman cuirass below a vertical unsheathed sword, point up, with the pommel resting on the neck opening of the cuirass and a Phrygian cap (the emblem of freedom during that period) supported on the sword point. The entire central device is a group of military trophies. Over this is a serpent holding in its mouth a scroll inscribed “This We’ll Defend”. Beneath the trophies are the Roman numerals for 1778.