Sometime in 1907-1908, John R. Neill drew a set of illustrations for Sleeping Beauty for the Children's Stories That Never Grow Old series. These were originally published in the Philadelphia North American newspaper, and later as individual story books.
I find it interesting that the images of the Princess are clearly influenced by Neill's illustrations of Princess Ozma from the Oz series. The poppies in the hair, practically a trademark characteristic of Ozma, are present and make sense in this case. Poppies have long been associated with sleep and death, and the soporific power of the poppies tie in well with the 100 years sleep. In Greek mythology, Hypnos and Thanatos are twin brothers representing sleep and death - they are often pictured in conjunction with poppies. And L. Frank Baum made memorable use of this symbolism with the deadly poppy field in the first Oz book.
Neill placed poppies in Ozma's hair in his first illustrations of her, in The Marvelous Land of Oz, and continued to use them throughout the series. I wonder if his idea was to represent a reminder of her years under enchantment - either as years asleep, or dead to the world?