Help on mark on Italian sword ca. 1580

[BladeMan]

Hello Everyone,

can someone help me out, point me a direction (to a book or another source) or may know anything about that mark on an Italian Sword dated ca. 1580. Wheter it is a makers mark, inspection mark or whatever. It is the only mark on the blade, at the Ricasso. I have seen similiar ones from/out of Veneto but never a single one like this.

Thanks!
Ray