1840 pattern. See The American Sword, Peterson #44. The blade marked US A D K 1863. Guard also marked A D K for inspector, Allen D King. Blade shows smooth glossy patina. Brass hilt with fine patina. Quillon bent. Surely served in the Civil War where musicians marched with the front ranks of the infantry with only these swords for defense. May well have served at Gettysburg (July 1-3 1863) which was the costliest battle in US history with about 50,000 casualties combined and culminated in the disastrous infantry charge by Confederate forces known as Pickett’s Charge. A well-used veteran of that monumental American war.