C.S. Lewis and J.R.R. Tolkien were two of Oxford’s Influential Inklings, but Lewis didn’t feel that he and Tolkien had influenced one another:
I don’t think Tolkien influenced me, and I am certain I didn’t influence him. That is, didn’t influence what he wrote. My continual encouragement, carried to the point of nagging, influenced him v. much to write at all with that gravity and at that length. In other words I acted as a midwife not as a father. The similarities between his work and mine are due, I think, (a) To nature — temperament. (b) To common sources. We are both soaked in Norse mythology, Geo. MacDonald’s fairy-tales, Homer, Beowulf, and medieval romance. Also, of course, we are both Christians (he, an R.C.).