They're lightweight and super-soft, too. The linen was a prize that Vasilii won, and he presented it to me, bless his heart. We used a good chunk of it to put some padding in his fighting shirts, to keep his lamellar armor from biting and pinching.
Did medieval women wear braies, as men did? Who knows - there are no extant pieces that I'm aware of, and period artwork never shows us what, if anything, might have been under ladies' chemises. Even if this isn't correct, I'm okay with that. I'll gladly be the rebel secretly wearing men's underpants with my clothes.
I read books, too. I'm scandalous like that.
P.S. - wore them to the even the first weekend in November, and they were SO COMFY. Also really warm under my dress, with a pair of tall socks underneath. Win.