Heavy Nubian / Nigerian Short sword...age? comments?

[katana]

Just won this ...a Nigerian short sword , 12" (30cms) blade which is 3/16" (4.5mm) thick, double edged . The hilt is bronze, (lost wax cast around the blade) This sword is quite heavy 3lbs 5 ozs (1.5 kgs) No scabbard .
The 'Gladius' similarities are obvious....a nice sword for close quarter fighting. I tried to research this type of sword with little sucess....however, I did find a 'similar' one on Therion Arms which had the addition of a cross guard.

http://therionarms.com/antiques/ttoy409.html

Not certain as to how old this piece is.....however the oxidation of the bronze hilt is consistant with some age. It has evidence of all three stages of oxidation....overall discolouration..dark brown copper oxide film. The formation of copper sulphate which creates thin, light green patches on the more exposed areas. Finally dark scabs and pitting.

Please if anyone has any information or comments they are most welcome/