This is the standard Staff officer's sword 1850 pattern of the US Union officers during the civil war.
It was based upon the French Model 1845 Infantry Officer's Sword.
It has a brass hilt with a dark shagreen grip (shagreen is a granular reversed leather or skin from an animal such as seal or shark, similar to suede); this is bound by brass wire.
The hilt has a lovely prominent "US" pierced into the right side of the basket.
Darken steel scabbard with two ornate ring suspensions.
Curved blade imported from France and marked Coulaux Frères poincons "B" and "D" stars used between 1830 and 1850.
Blade is engraved on one side "US" and "E Pluribus Unum" ( "Out of many, one"—is a phrase on the Seal of the United States, it "alludes to this union" between the 13 states and federal government.
On the other side the blade is engraved with the American Eagle.
Marked FBD on the hilt, stands for F. Delacour & Bakes, sword maker in Paris during the Second Empire.
" Coulaux Frères "
Officer wearing the sword