Two miniature Knifes/Daggers

The bottom knife on the main picture is a letter opener, made of brass with an inlay  handle. Some of the inlay bits are missing. Tarnished but a nice acquisition to your stationery collection.
The second one has me puzzled as it it too well made and elaborate for an letter opener. I would think a ceremonial item as it is sheathed and has a chain with an attachment hook. The blade is grooved and decorated with engraving. Slight surface corrosion on it. The sheath is stitched leather and has a small flapped hole cut in it by the blade but no loss of leather. The handle looks like horn with concentric rings at both ends. Amazingly well made with detail.