 Lewis remembered rainy summer days from his youth and Digory is faced with the same woe in the novel.Additionally Digory becomes a professor when he grows up, who takes in evacuated children during World War II.The character of Andrew Ketterley also closely resembles Robert Capron, a schoolmaster at Wynyard School, which Lewis attended with his brother, whom Lewis suggested during his teens would make a good model for a villain in a future story.