My father picked up a F. W. Holler army dagger and sheath back in the '70s or '80s and it came with this portepee. The length of the strap is only about 14 inches (with it doubled up). I get the sense that the color of the bottom area of the knot may once have been maroon or puplish, though it has by now faded to the nondescript color that you see in the second picture.
Your Portepee is for a Heer Officer sword not a dagger. The Heer Officer dagger requires a different Portepee with round cord straps instead of a flat leather strap.
"You can't please everyone, so you've got to please yourself." Ricky Nelson
Thanks you two... I am amazed at the depth of knowledge on display on this site. I find myself reading threads just for the discourse between experts, even though I have only the vaguest notion of the subject at hand.