Edmund Dulac's The Real Princess (or the Princes and the Pea).
Sylvie's nickname is "Button." I think I should change it to "Pea."
I would like a copy of this illustration, I think, to hang on my bedroom wall. Artsy Craftsy has one for sale.
This particular illustration is mentioned in Patricia Morrisroe's Wide Awake, which I prattled on about in the previous post. Morrisroe and her husband spent a Christmas at the Ice Hotel in Swedish Lapland, where he presented her with a copy of Stories from Hans Christian Andersen. (I'm not sure if he presented her with the reproduction I linked to -- what a beautiful book at a good price -- or a first edition.)