A sail guard sword - blade for ID

[fernando]

This one was added to my little collection in unusual circumstances. Not that i don't like it, on the contrary .
I will call it Portuguese and not (also possibly) Spanish, because it belonged to a Portuguese collector, for one. In principle from the XVII century ... until better opinion.
The hilt forming what we call over here a sail guard sword; the scallop a nice addition to the traditional style. The grip in ivory (i presume) with nice patina.
The rapier blade (to call it so) measures 87 cms. with 19 M/M width. The wole sword is rather light, with only 695 Grams. Point of balance approx. 7 cms. from the guard.
What troubles me is the inscription on the blade; whether it is a maker's mark or some kind of allusion text, i can't pick the slightest trace. I believe that this is the type of lettering that it will not be identified by simply managing to read it but potentialy by someone already familiar or experienced with it, like having seen or possessing a blade with similar characters. In any case it would be great (greatest) if some forumite pops up with the solution, whatever the method.

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