In Chapter 8 of Rainbow Valley, Walter reads and recounts his favourite stories to the Rainbow Valley gang. He concludes by having a premonition of The Piper.

Walter, lying on his stomach among the fern, was reading aloud to Mary and Di and Faith and Una from a wonderful book of myths wherein were fascinating accounts of Prester John and the Wandering Jew, divining rods and tailed men, of Schamir, the worm that split rocks and opened the way to golden treasure, of Fortunate Isles and swan-maidens. It was a great shock to Walter to learn that William Tell and Gelert were myths also.

In chapter 13 of Emily’s Quest, Ilse vents her frustration with Perry Miller to Emily:

Perry has changed his politics just for the sake of getting into partnership with Leonard Abel. There’s Stovepipe Town for you. Oh, he’ll be Judge Miller and rich as wedding-cake–but–! I wish he had had a hundred eyes so that I could have bored them all out! This is one of the times I feel it would be handy to have been a bosom friend of Lucrezia Borgia.

“Who was an excellent and rather stupid woman beloved for her good works.”

“Oh, I know the modern whitewashers are determined to rob history of anything that is picturesque. No matter, I shall cling to my faith in Lucrezia and William Tell. Put that picture out of my sight. PLEASE, Emily.”