I'm afraid that story is nothing more than a fairy tale. That sword is not a 12th century form but looks far more like a Petersen Type D which would put it in the 10th century. I say form because looking at the pictures the construction seems to be all wrong for that form. The pommel appears to be one piece and the grip seems to be a welded or brazed ovoid form and attached to both the upper and lower hilts. The inscription also seems to be very suspect on that sword and not in keeping in form or purported content at all with the supposed age of the sword. Now it could be that I'm just looking at crappy pictures and that deterioration is what I'm seeing but it seems very suspicious to me.
I also didn't see any substantiating evidence whatsoever that it was actually gifted by Ivan the Terrible (why would he have been gifting a 10th century sword in the late 16th century?) to anyone. Nor did they present any evidence whatsoever that it was used in this battle at all. Would have, could have, should have, might have makes for fun stories but isn't evidence of anything.
Buy the sword not the story, and in this case I wouldn't even buy the sword.
I think this "archaeologist" is simply throwing out some crazed theory in a bid for publicity.
