Main article: Religion in The Chronicles of Narnia
A convert to Christianity in later life, Lewis had authored a number of works on Christian apologetics and other literature with Christian-based themes before writing the Narnia books. The character Aslan is widely accepted by literary academia as being based on Jesus Christ. Lewis did not initially plan to incorporate Christian theological concepts into his Narnia stories. Lewis maintained that the Narnia books were not allegorical, preferring to term their Christian aspects a “supposition”.
The Chronicles have, consequently, a large Christian following, and are widely used to promote Christian ideas. However, some Christians object that The Chronicles promote “soft-sell paganism and occultism” due to recurring pagan imagery and themes.
This is a direct quote from Wikipedia.