Awesome backstory for an item everyone has touched in one way or another in their games.
Perhaps lost in history but now realized by that collector or Mr. Evil is that the sum is greater than the parts. Individually the swords are only +1. But when many swords are massed there is some additional effect that takes place (each sword becomes +3, morale boost, berserk rage, haste, perhaps being near or touching forge grants mind control over sword wielders, etc).
Items (Melee Weapons) (Magical)