A blade for coments; old, early, or very early

[fernando]

The pictures are lousy, but i couldn't wait to show this one.
Found (coincidently?) near the ruimns of a Roman citania (settlement), in northern Portugal.
Blade 27,5 cms (7 3/4"), hilt (tang) 13,5 cms (5 1/4").
Quite a long tang; could it have a large pomel or hilt, to 'consume' some of its length?
The guy who acquired it thought he better clean it, as it was completely envolved in rust; but i reckon (and told him) he nearly reached the reasonable limit.
What do you guys think this is; something weapon like and seriously old ... even early?
Would better pictures be vital?
Fernando

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