Rosemary Sutcliff imagined the story behind the magical White Horse of Uffington for her 1977 children’s book (historical fiction) Sun Horse, Moon Horse. It involved the Epidi (meaning “Horse People”), a tribe that had also appeared in her earlier 1954 novel The Eagle of the Ninth. In the author’s note to the original publication she wrote:
If any of you who have read it have also followed the adventures of Marcus and Esca in The Eagle of the Ninth, and think that Lubrin’s people are not very like the Epidi who they found when they went north to rescue the eagle of the lost legion, I can only say that when I wrote that story, I had not read (T. C. Letherbridge’s bokk) Witches. And if I had, I would have made them a slightly different people. Though, of course, they might have changed quite a lot in more than two hundred years.
Earlier she explained the origins of her story, in a book by T. C. Letherbridge and an unusually old White Horse:
