Rapier or smallsword PIERCED blade for comment

[fernando]

Originally Posted by Valjhun

... too long for a dagger...

Not necessarily ... i mean, there were hunting (plug) bayonets with blades reaching the length of your example and even more.

Originally Posted by Valjhun

is that an original tang or just a soldered piece? I would vote for the second option, I'm not sure thou....

Most certainly the second option; blades usually brake by their body but probably this one broke by the tang. Then the (new) owner shortened its point and welded such bizarre tang, transforming it into what it is now, whatever its use... even a defence side arm. This would also give logic to a weapon with such blade length.
The cross is apparently from the period, added to the blade for its new pourpose.
Pardon me if i am talking nonsense .