A white rabbit named Peter joined the Elgar family in 1905. He appears in numerous items of correspondence and is credited, as Pietro d’Alba, with writing the words for Elgar’s songs The torch and The river.
Elgar also welcomed musical criticism and suggestions from Peter; for example, after conducting the London premiere of his second Wand of youth suite in 1908, the composer wrote to him:
My dear Peter,
Your idea—the vigorous entry of the drums—was splendid. Thanks.
This according to “Peter Rabbit: The biography of an inspired bunny” by Martin Bird (The Elgar Society journal XXI/1 [April 2018] pp. 32–39).
Below, the composition in question; Peter’s contribution begins around 15:30.