The Belief of Men

[Maedhros]

From Morgoth's Ring: Athrabeth Finrod Ah Andreth
'Yet among my people, from Wise unto Wise out of the darkness, comes the voice saying that Men are not now as they were, nor as their true nature was in their beginning. And clearer still is this said by the Wise of the People of Marach, who have preserved in memory a name for Him that ye call Eru, though in my folk He was almost forgotten. So I learn from Adanel. They say plainly that Men are not by nature short-lived, but have become so through the malice of the Lord of the Darkness whom they do not name.'
said Andreth.
That's an interesting belief that early men had. That they were inmortal too from the beginning. Could this be the way that Melkor used to turned Men against Eru and the elves?
Che pensi tu?

[Dark Elf]

That's one of my favourit stories in MR.

As Atthrabeth said later on is the story;
All that he though seemed good, for he had great knowledge. But even more and more he would speak of the Dark. 'Greatest of all is the Dark,' he said, ' for it has no bounds. I came out of the Dark, but I am it's master. For I have made Light. I made the Sun and the Moon, and the countless stars. I will protect you from the Dark, whitch else would devour you'.

Then we spoke of the Voice. But he's face became terrible; for he was angry. 'Fools!' he said. 'That was the voice of the Dark. It wishes to keep you from me; for it is hungry for you.' Then he went a way, and we did not see him for a long time, and without his gift we were poor.

By the first men that hadn't yet meat the Elves would not know that the Voice was Eru. It is easier to belive something you see, as it is more impressing. Thus, by gifts and talking about the threatening Dark, Melkor made the first men belive that he had created the Sun, Moon and Stars. To them he, Melkor, the creator, bringer of gifts, in a shape , at that time, that was beutiful would protect them against the Dark, whitch, as he claimed, would devour them. It would be easy to belive that if you knew not the truth.

[Finrod Felagund]

I've only read it once, but at first glance it is similar to the Judeo-Christian Garden of Eden and Genisis... not much, but succumbing to temptation and loosing grace seems to be the theme.
I think Tolkien may have deciced Men of ME needed their own version

[Tar-Palantir]

It said "long-lived" not Immortal. Men perhaps lived 1000 years?