PLEASE, PLEASE snip out the quoted text or do something to shorten your messages when you only wish to ask one question! I think you were just asking this one question. It was hard for me to tell.

Anyway, to answer your question, the Helm's history is a bit tattered. In UNFINISHED TALES Christopher Tolkien says that the history of the Helm ends with the destruction of Dor Cuarthol, but that his father had intended to extend it beyond that. He was eventually going to have Turin wear the Helm in Nargothrond and perhaps in Brethil, but these changes were never introduced to the Narn.

Even if we assume for convenience' sake that the canon may include the Helm in these later episodes of Turin's life, since it is nowhere else mentioned in the Middle-earth stories, we must conclude that it was either lost in the destruction of Beleriand or the destruction of Numenor. The Downfall is as far as we can reasonably extrapolate, I'm afraid.

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