Something like a year and a half, 2-ish years ago, I read a trilogy of novels centered around a Celtic (Irish maybe?) myth of a young woman whose stepmother turned her brothers into swans, and she was forced to leave her family to do a task (weaving, maybe?) while not speaking to anyone for a long period of time to get them back. I want to say about the time I found them, the 3rd one was new, or at least I think I picked it up from the ‘new’ shelf and then ran down the first two.
Some Googling has turned up the name Etain, but Etain, Celtic Swan Myth, Irish Swan Myth, etc., turn up nothing in the library’s and search functions, and books that are not what I’m looking for in Amazon’s.
I hope this rings a bell with someone - I’ve tried to describe it to various other ‘all things Celtic’ enthusiasts, only to be met with the ‘she’s done gone and lost it’ look, so I’m starting to wonder if I really read them at all!
haven’t read it, but the name “The Seventh Swan” might be a jumping-off point. IIRC, this is a spin-off of the basic fairytale your trilogy is based on. general background plot spoilers: Evil Stepmother enchants seven brothers, turning them into swans. sister can break enchantment if she weaves a shirt of nettle for each one without uttering a single sound in the process. in the story, some king takes a shine to her and marries her, but soon she’s accused of witchcraft by the populace due to her strange hobbies. at the point of being burned at the stake, her swan brothers fly back to her and she throws the shirts over them, breaking their curse and finally allowing her to speak and explain herself. unfortunately, the forced meeting meant she didn’t quite finish the last shirt, so one brother is left with a swan wing instead of an arm. that’s where the fairytale generally ends.
“The Seventh Swan” follows from the fairytale, telling the story of the last brother. whether or not this was part of a trilogy, i don’t know. but maybe it will at least get you pointed in the right direction.
i think the original fairytale is usually just called “The Seven Swans”. it may be by Hans Christian Anderson.