Where were the `Blades of Westernesse` forged?

[Morthoron]

Originally Posted by Cirdan

If the North-kingdom perished more than 1000 years beforehand (and was sundered from Gondor even earlier -with the brief exception of Firiel's marriage to Arvedui), then how is it that Denethor recognized this blade as an Arnorian relic?

If it were wound with spells, the handle and the blade itself most certainly would have runes on it, possibly in Adûnaic. Denethor was enough of a scholar to detect an ancient variant of Gondorion writing.