From The Heroes of Might and Magic III wiki
|Effect: Worn on the head, this item increases hero's knowledge skill by +5.|
|Your army is ambushed by a small tribe of wild (and none too bright) Orcs. You fend them off easily and the survivors flee in all directions. One of the Orcs was wearing a polished horned helm. Figuring it will make a good souvenir, you take it.|
Hellstorm Helmet is a major class artifact, that is equipped in head slot. It increases hero's knowledge skill by +5.