Some names I thought of:
[name_f]Antoinette[/name_f]
Celymene
[name_f]Guinevere[/name_f]
[name_u]Dione[/name_u]
[name_f]Merope[/name_f]
[name_f]Marinette[/name_f]
[name_f]Juliane[/name_f]
[name_f]Victoire[/name_f]
[name_u]Meredith[/name_u]
Which name do you like? [name_u]Or[/name_u] do you have name suggestions yourself?
I like Celymene best, but [name_f]Antoinette[/name_f] is also really pretty.
[name_f]My[/name_f] favorites are [name_f]Guinevere[/name_f] and [name_f]Victoire[/name_f], but I have some more ideas 
(aka an extensive list 
) Let me know what you think!
(yes I looked at names from the period, so they are accurate to the time! I do my research 
)
Alianor/Alianora
Amycia
Admiranda
[name_f]Avelina[/name_f]
Annor/Annora
[name_f]Ayleth[/name_f]
[name_f]Ameline[/name_f]
Avicia
Athelina
[name_f]Amia[/name_f]
[name_f]Adelie[/name_f]
Alainne
[name_f]Avelot[/name_f]
[name_f]Beatrix[/name_f]
[name_f]Betta[/name_f]
Celestria
[name_f]Clementia[/name_f]
Clericia
[name_f]Edit[/name_f]
[name_f]Eda[/name_f]
Edolina
Elviva
[name_f]Elvina[/name_f]
Edelina/Edeline
Etheldreda
[name_f]Emelina[/name_f]
[name_f]Emony[/name_f]
Estrelda
Eilaria
Elaria
Estrild/Estrilda
Evelune
Fluri
[name_f]Florie[/name_f]
[name_f]Felise[/name_f]
Heloise/Heloisa
Gracia/Gracia
[name_f]Golda[/name_f]
[name_f]Grete[/name_f]
Hillaria/Hilaria
[name_f]Ilaria[/name_f]
[name_f]Idony[/name_f]
[name_f]Idonia[/name_f]
Ivette/Ivetta
[name_f]Imeda[/name_f]
[name_f]Imma[/name_f]
Isemay
Ismena
Isolda/Isolde
Laurencia/Laurentia
[name_f]Maud[/name_f]
Maudelyn
Milicenta
Miriel
[name_f]Minna[/name_f]
[name_u]Nesta[/name_u]
[name_f]Osanna[/name_f]
[name_f]Orabella[/name_f]
Petronella/Petronelle
[name_f]Philomena[/name_f]
Quenilda
[name_f]Rosamond[/name_f]
[name_f]Rowena[/name_f]
[name_f]Sabina[/name_f]
[name_f]Sibylla[/name_f]
[name_f]Tilla[/name_f]
Ulia
Thank you so much for the effort! I like a lot of those names, it’s going to be hard to decide! I love Alianor, [name_f]Adelie[/name_f], [name_f]Avelot[/name_f], [name_f]Edeline[/name_f], [name_f]Heloise[/name_f], [name_f]Isolde[/name_f], Maudelyn and [name_f]Rowena[/name_f] the most I think. Those are all amazing names!
A lot of these feel more [name_u]French[/name_u]. [name_f]English[/name_f] princesses in that time often had what have become through the years quite popular and overused and potentially ‘boring’ names, compared to a lot of your elegant suggestions.
Suggestions/names of actual [name_f]English[/name_f] princesses/nobles around the 13th century
[name_f]Adela[/name_f]
[name_f]Adeliza[/name_f]
[name_f]Isabella[/name_f]
[name_f]Isobel[/name_f]
[name_f]Berengaria[/name_f]
[name_f]Matilda[/name_f]
[name_u]Joan[/name_u]
[name_f]Alice[/name_f]
[name_f]Joanna[/name_f]
[name_f]Eleanor[/name_f]
[name_f]Margaret[/name_f]
[name_f]Philippa[/name_f]
[name_u]Anne[/name_u]
[name_f]Mary[/name_f]
[name_f]Gwenllian[/name_f] (welsh not English)
[name_f]Elizabeth[/name_f]
[name_f]Katherine[/name_f]
[name_f]Beatrice[/name_f]
[name_f]Aveline[/name_f]