The Met says: “The silhouette of the 1910s is a revival of the Directoire and Empire styles, but here it is blended with a turn-of-the-century monobosom. Once again, a new silhouette was founded in reference to past style. The revealing neckline conforms to an unsupported bust, creating a soft, languorous silhouette.”
This is going to bother me so much, I recognize that motif from somewhere. Is it related to Marie Antoinette maybe?
TThe motif of the three ostrich plumes is from the coat of arms of the Prince of Wales, adopted after the Battle of Agincourt
Edit again: I didn’t think it was a fleur de lys. I do know what that looks like! It reminded me of something from Marie Antoinette’s bed but now I’m thinking I might have gotten that confused with one of the beds at Hampton Court.