Just to add to the ratiocination:
It is worthy of note that similar hilt configurations with this kind of pierced openwork in the elements are seen in "Armi Bianchi Italiene" (Boccia & Coelho, 1975, Milan) example #142, shown as from Veneto c.1480-1500. Another two hander #584 c.1603 is seen with similar quadreform pierced pommel and quillons on guard (op. cit.).
Veneto is to the west of Venice, and there is a region known as Cavaion Veronese. This is simply worthy of note because of the similarity to the spelling of 'cavaio'. It seems likely that the 'cavaio' spelling is phonetically sounded to the word 'cavallo', which of course in Italian refers to horse.
The term cavallo is used describing a number of presumably cavalry or horsemans swords.
As is often the case, it seems there is always potential for classical and perhaps even mythological allusion in symbology in weapons with markings, inscriptions and phrases. With the term 'cavaio marino' it does seem to apply more to 'seahorse', as noted with the name of the galley at Lepanto.
It is not common however to put the name of an individual, ship or otherwise in the fuller of a sword as far as I am aware.
It seemed likely that perhaps heraldic metaphor might come into play with the seahorse in this case, and nothing specific was apparant, however in mythology the sea nymph Thetis, mother of Achilles, is sometimes depicted on a sea horse carrying the arms forged by Vulcan for Achilles.
("Fictitious and Symbolic Creatures in Art", John Vinycomb, 1909).
The weapons of Germany and Italy were often closely aligned in these times, and as has been noted, the mans head mark is similar to some of Solingen. The phonetic spelling of cavaio seems to reflect other instances where names or words spuriously applied in Solingen on blades often had spelling or other subtle errors.
We know that in Solingen blades were often tailored to certain markets and it is now believed that the names or words in blade fullers may well have been chosen and used to appeal to these markets. For example, the legendary Andrea Ferara name of course was favored in Scotland and was invariably placed on these broadsword blades; Sahagum blades often went to the north countries; Tomas Aiala is on rapier blades for export to Spain and its colonies.
Could the 'cavaio marino' carry classical allusion ? and perhaps be considered a 'brand' or blade type to appeal to Italian market?
Fanciful ? perhaps, but then sometimes such thinking is fun and at least worth considering.
