Mithra-ndir: Gandalf and the Roman cult of Mithras.
J.R.R. Tolkien described The Lord of the Rings as a fundamentally Catholic work. But a close reading of the epic novel reveals many more influences, including a connection between Mithras and the wizard Gandalf, whose Elvish name is Mithrandir.
The key point is that Tolkien himself said he did not intend the transformation of Gandalf the Grey into Gandalf the White to be “a retelling of the Christ story.” Instead Gandalf experienced “a transformation and rebirth, not a Christlike resurrection.” This corresponds to the Tauroctony of Mithraism. Some confusion is understandable given the similarities between Christianity and Mithraism.
These connections between Mithraism and Christianity coupled with the previously mentioned fact that the London Mithraeum was unearthed the same year as the publication of both The Fellowship of the Ring and The Two Towers, suggest that while these Mithraic resonances may not be intentional, they are strong, especially given the similarities between Christ and Mithras.
My fellow F&SF fans may know that Mithraism also figures in Poul and Karen Anderson’s The King of Ys.