To me it looks like 17th century west European sabre. Many of them were produced and were in use in those days I think. And the hilt is very "natural" for such sabres too, so I wouldn't call it a rapier hilt. I can't tell what are this markings, maybe they are similiar to those used in Caucas as you suggest, I don't know, I haven't got any book on markings by now around me so I hope that other will help you with this. But I saw something similiar on other sabre (not the same thought but close) which was called Venetian. And I don't mean the markings of Genua "sickle", by the way which we could call similiar too
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This one looks anytique and complete. I think it's quite good. But one thing is worrieng me. I just saw on one of the Italian auction house the edged weapons made in 19th century from so called historical period. Some of them looks very antique on photographs. Anyway, how to belive the photographs from now
Ragards!