C.S. Lewis dedicated The Lion, the Witch, and the Wardrobe to his goddaughter, Lucy Barfield, and used her name for one of the main characters (source).
C.S. Lewis wrote in his short essay "It All Began with a Picture…" that he first thought of The Lion, the Witch, and the Wardrobe when he saw an image in his mind of a Faun carrying packages in a snowy wood and holding an umbrella. Next, he thought of Aslan, and then he built the story from there (source).
The name "Aslan" means "lion" in Turkish (source).
C.S. Lewis and J.R.R. Tolkien were colleagues at Oxford, close friends, and fellow members of a literary club called "The Inklings." They often read one another's works in draft form and Tolkien was instrumental in Lewis's conversion to Christianity. Although they drifted apart in later life, their friendship remained an important formative experience for both men (source).
C.S. Lewis's full name is Clive Staples Lewis (source).
C.S. Lewis wasn't the first person to write a fantasy in which the main character gets to the magical world through a wardrobe – E. Nesbit was! Her story "The Aunt and Amabel," published in The Magic World in 1912, also features a little girl who goes through a wardrobe in a spare room into another world. For those of you who are keeping score, that means Nesbit's wardrobe story was published almost 40 years before Lewis's!