Ancestors of yataghans

[TVV]

Jeff, this is exactly what I started to write: Scythians did not have stirrups and it would have been hard for them to use swords while mounted. However, I always associated the invention of the stirrups with the Huns, or perhaps even the Sarmathians, and not the Goths, but this is immaterial to the discussion at hand. It was later than 1500 B.C. by all means.
Toa dd something more to the discussion, here is a picture of a Thracian mahaira, which in its essence is almost identical to the kopis, if not the same thing.