Fibula?

[Medicus matt]

I don't think that it's a scabbard slide. Look at the angle of the pins; if you imagine trying to recreate the sort of curvature you'd need for a slide (reversing the current curvature that was presumably caused by compression whilst it was in the ground), the pins would be angled in at least 45 degrees and neither the head or tail would lie flush with the surface of the scabbard. Don't know what it is, but it doesn't really look like any slider I've seen. Looks like the whole thing was designed to lie flat against something. Could be more furniture/chest decoration.