Dagger: Russian or ...what???

[ariel]

Folks,
Just wanted to show you a dagger. Pics are lousy, because there are two only such daggers in existence: one private, another in State Historical Museum in Moscow. The latter has a golden inscription on the spine that it belonged to some russian noble, beginning of the 16-th century. It is narrow, ~20 " long, the edge is on the concave side, and there is a T-spine.
There are also 2 or 3 illustrations of that dagger in the literature showing the arms of Russian nobles.
The origin is complete mystery. I found only one +/- similar one, in the Furussiya book where it was described as ghaznavid, 11-12 cen.
Do you have any ideas where it could have come from, its predecessors ( if any) or anything else.
Cannot put better pics, sorry. Exercise your imagination:-)