I do know some about this. I am sure you would find this in the threads Boromir88 has so graciously given us links to, but here is some of what I know.
I know for a fact the he drew some of his inspiration from
Beowulf. As I am only a junior and have not yet read it I cannot compare, so I will leave that up to those who can. He also got some ideas from this old Finnish folktale called the
Kalevala.
Wait!!!!!!!
I just found some things in a book I have. it is called
The Magical Worlds of The Lord of the Rings its by David Colbert. I think it is a good book. It may not be totally correct with everything, but it does give some insite into stuff.
Anyway you were asking about mixing influences. Similar things in Tolkien's works and others. Ok here you go.
The
Kalevala -
Kalevala creator = Ilmatar <---> Iluvatar = LotR creator (they are close)
Just as the ring causes corruption and war where ever it goes in LotR there was a magic item, the Sampo, that had the same results in the
Kalevala.
Thats just some of the similarities. For more you could get the book or read the Kalevala for yourself, but until someone tells me that I am, or the book is wrong, I will believe it for now.
Beowulf-
In the same book Colbert quotes another book, which I also have, but it is harder to find stuff in,
Road to Middle Earth by T.A. Shippey. Shippey stated that Legolas describes Meduseld (the Golden Hall) with the same line the describes the mead hall in
Beowulf. "The light of it shines far over the land." Which is true if it is in Beowulf because I found it in LotR.
Again
the magical world has more similarities described in it based on how Colbert see things, but I would agree with him on some, if not most of it. It is one of those things that you have to read for yourself and you decide. And if its not right, at least it get you thinking about things.
I am sorry this is so long. I hope that that isn't a bad thing.