When was + Backstab Damage added to weapons?

[NASA]

Curious as to what expansion added the + Backstab modifier to some weapons.

[Shiftin]

velious

http://everquest.allakhazam.com/db/item.html?item=6887

[Phallax]

I think that mod was retro added. I dont think any mods occurred until GoD.
Could be wrong tho

[Droop]

I remember these mods during LDoN when I came back. I don't remember them back in classic through Velious though...keep in mind I never hit high-end Velious or Kunark content then which could be why I don't remember it.