autobiographical aspects in Middle-earth?
 

I just looked at the August page for Tolkien 2004 Calendar , by Ted Naismith, featuring Eowyn and Eomer. The quote on the page is "...Lady Eowyn wore a blue mantle of the colour of deep summer night, and it was set with silver stars about hem and throat. Faramir had sent for this robe and had wrapped it about her; and he thought that she looked fair and queenly indeed as she stood there at his side. The mantle was wrought for his mother, Finduilas of Amroth, who died untimely, and was to him but a memory of the loveliness in far days and of his first grief..."

It seems a clear allusion to his early days at Sarehole and loss of his mother, even more then the loss of Aragorn's mom or Frodo his parents, since those two seem to have had generally happy childhood's, more then one assumes Faramir did.
Also, there may be other autobiographical bits in the character of Faramir, who is basically an intellectual, eager to learn from Gandalf, who does not "love the bright sword for its sharpness, nor the arrow for its swiftness, nor the warrior for his glory."
Are there other such, as it seems there may be, such strong autobiographical allusions, and were they conscious or not, like World War I battlefields for Mordor?

Religous
 

Tolkien was a religious man and he incorporates a lot of religion into his story, but I don't know if that is really what you are looking for in this thread or not?

As a quick WW1 scene I think Tolkien's writing on Mordor, or in particulare Gorgoroth seems like his memories of "no mans land."

This short discription would seem like the dreaded "no mans land." The words "gazed" could be Tolkien remembering of his past as he looked out upon the land. Then "burned" and "choked" are great descriptive words. There's more however...

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Could this be Tolkien looking beyond "no mans land?"