One very similar is the one of this set, "arabian nomads" (http://www.collectobil.com/catalogue/items/3585.htm), which I happened to have, in my Portuguese days :) ... But it wasn't exactly the same knife. The shape of the blade was very alike, though, very pointy ... Those pots were great! I hope to get them again, some day!
Uhm, sorry, ... Getting off topic with such a simple subject, what a shame! ... The knife you showed, from 3409 "City Defence" (acc. to Collectobil.com) is like this:
o--(---
more symmetrical
however
than I could show here ...
and the one of 3585 is more like this:
v--|---
The knife you found may be thought to have been (generaly) replaced by the common dagger that is now found in many sets, that I first saw with the black figure of set 3794 (http://www.collectobil.com/catalogue/items/3794.htm).
I agree that the old knights dagger is quite more like out of a Shakespeare play ;)
G.--
:)