The handle end may be mounted with a clear polyester film strap; probably 1/2" wide would be plenty of support.
The business end of it -- sharp, I presume -- may be mounted with a formed rod mount made of spring steel (piano wire); probably .032 diameter would be a good size. To avoid scratching the metal of the sword, pad the mount with shrink tubing. Or, maybe you could use stainless steel picture framing wire as a mount, also padded, of course.