Because of Lewis’s typological approach to his use of sources, it is possible to see Aslan not just as a straight allegory of Christ but as embodying elements from other mythic systems; in this case, Balder, a figure from Norse mythology. This is supported by Lewis’s known love for northern myths and his particular reaction to the lines about Balder from Longfellow’s “Tegnér’s Drapa.”
"Balder the Beautiful: Aslan's Norse Ancestor in The Chronicles of Narnia,"
Mythlore: A Journal of J.R.R. Tolkien, C.S. Lewis, Charles Williams, and Mythopoeic Literature: Vol. 22
, Article 7.
Available at: http://dc.swosu.edu/mythlore/vol22/iss3/7