I didn't see Jeanne de Montbaston in the list yet. She was an illustrator/illuminator who worked with her husband, Richard, at their bookmaking atelier in Paris, around 1320 to 1355. She outlived him, and kept the business going for a number of years, so I think she must have also done scribal work. Her illustrations & illuminations appear in some of the world's most beautiful books. (examples at the Getty: http://www.getty.edu/art/collection/artists/28932/jeanne-de-montbaston-french-active-about-1320-1355/)
She's also famous for the notorious 14th-century edition of the Romance of the Rose with illustrations of nuns harvesting penises off a penis tree (Paris, Bibliothèque nationale de France, MS. Fr. 25526). You can view the entire manuscript online: https://gallica.bnf.fr/ark:/12148/btv1b6000369q.r=MS.%20Fr.%2025526?rk=21459;2
--yours, K
Interestingly enough, I read about that book after I stumbled upon an article about Christine de Pizan, a French court poetess born in Venice. She was a harsh critic of the Romance of the Rose, partly on the grounds that it was misogynist (I am not sure if she used this term). The information on her isn’t very clear, because some of it that I read is contradictory and some of it seems to be speculation. She was the widow of a royal secretary (I am noticing a pattern), and was able to write in chancellery script, and may have been a copyist. Some sources speculate that she was also an illuminator, but I doubt that. She mentions a female border artist (manuscript production was very specialized back then), named Anastasia, and praises her as the best. Some sources conclude from that to say that she preferred to work with women. However, it may be that she preferred to work with the best, and gave Anastasia as an example of a talented woman (the book was about women). One of the conflicting things in the online sources is how typical women artisans were, however, they seem to be less rare than women poets.