Corona di Mario Diaz
Corona di Mario Diaz was an Italian company based in Milan, active from the mid-thirties. Unfortunately it is not known an exact date for the founding of the company, not to be confused with the same name "Corona" American and English brands. The company was active (at least by some registered trademarks) in the field of mechanical adding machines, but the only registered trademark pertaining to pens is CIP (Reg. Gen. N. 116011).
It is unclear whether there is any relationship with the Corona (Reg. Gen. N. 90853) trademark registered by Luigi Vigorelli in 1945. The production, as evidenced by the order of 1952 shown in the figure at the side, went even after the war, but again it is not known until when the activity has continued.
The company produced good quality celluloid pens, featuring a Corona marked gold nib, with the brand name imprinted on the body, between two circles, in nineteenth-century characters. It's quite interesting, at least in the case of the sample in the figure, the decoration with rings alongside the inscription itself.