So, apparently Jack based the Professor in The Lion, the Witch, and the Wardrobe on John.
But what's funny, to me at least, especially after reading CotIG, is that in the 2005 movie adaptation of the book, the Professor looks kinda like Charles...
(And on a related note, I also find it funny that the 2005 adaptation was directed by Andrew Adamson, and the whole story revolves around the fact that the Pevensies are Sons of Adam and Daughters of Eve in Narnia...)