Renaissance style stiletto

[zalmoxis]

I think this is a late 17th century early 18th century dagger.
You are right about the shape and being modified just adding the skin.
Looking at the blade it does not seem to have been modified from a small sword.
Second half of the 17th century had all kind of pillow swords and parring daggers with smaller cross guards.
But is just me I could be wrong.