Note: I am not a professional fashion historian. If you spot any inconsistency or outright fallacy somewhere in the picture descriptions please feel free (or even better, obliged) to let me know!
1475, Flanders - Ghent
Bodleian Library
MS. Douce 365: Moral and religious treatises,
fol. 115r - Margaret of York at prayer
source (LUNA)
Margaret and the other lady closer to her wear later 15th century variants of the fitted gown, derived from the houppelande, and a black hood or frontlet with steeple hennin. The fitted silhouette of the gown is accentuated by the wide belt, worn so tight around the waist it almost seems to merge with the dress.
(For an even later example of the houppelande’s evolution, although English, see this beautiful funerary brass. The only conspicuous vestigial part of the dress that is referencing its predecessor (the houppelande) is the overturned collar/lapels.The belt is narrow and worn low, reduced to a decorative function - the dress is presumably fastened with hidden lacing in the front. Technically, the gown has become an overkirtle.)
The third kneeling lady wears an overkirtle with wide opening in the front, held together with horizontal lacing. Underneath a kirtle would be worn and also maybe an embellished stomacher (also known as a placket). The bust seems flattened and the torso straight - the inclination towards this kind of silhouette foreshadows the imminent advent of the corset.
(Several similar examples (all by Memling): 1470s detail of kneeling daughter of a donor from Donni triptych, 1480 detail of Mary Magdalene from Adriaan Reins triptych, 1485-90 lady with a pink)
later 15th century (ca. 1470)
Bibliothèque de Genève
Ms. fr. 189: Tristan en Prose
fol. 177v - “Tristan welcomes the girl sent by Isolde”
third quarter of the 15th century (1450-1475) France - Auvergne?
The Hague, Koninklijke Bibliotheek
74 G 27: L’Epistre d’Othea by Christine de Pizan
fol. 41v - Hero and Leander
http://collecties.meermanno.nl/handschriften/showmanu?id=1151&page=1&page_size=40
Hero and Leander is a myth relating the story of Hērō, a priestess of Aphrodite who dwelt in a tower in Sestos on the European side of the Dardanelles, and Leander, a young man from Abydos on the opposite side of the strait. Leander fell in love with Hero and would swim every night across the Hellespont to be with her. Hero would light a lamp at the top of her tower to guide his way. Succumbing to Leander’s soft words, and to his argument that Aphrodite, as goddess of love, would scorn the worship of a virgin, Hero allowed him to make love to her. This routine lasted through the warm summer. But one stormy winter night, the waves tossed Leander in the sea and the breezes blew out Hero’s light, and Leander lost his way, and was drowned. When Hero saw his dead body, she threw herself over the edge of the tower to her death to be with him.
-from wikipedia
later 15th century (ca. 1470)
Bibliothèque de Genève
Ms. fr. 189: Tristan en Prose
fol. 20r - judgment over an adulterous woman
third quarter of the 15th century (1450-1475) France - Auvergne?
The Hague, Koninklijke Bibliotheek
74 G 27: L’Epistre d’Othea by Christine de Pizan
fol. 59v - “Arachne boasts to Minerva about her weaving and is changed into a spider”
http://collecties.meermanno.nl/handschriften/showmanu?id=1151
15th century France
Bibliothèque nationale de France
Français 19137: Roman de la Rose
fol. 1r - detail
http://romandelarose.org/#book;Francais19137

Note that the lady’s gown does not seem to have any closure in the front - it is meant to be worn with tight belt, as depicted. The gown is lined in fur, which is shown off at the cuffs and the lapels - which really evolved from the collar of a houppelande, later worn turned over. The front opening is filled with what seems to be a stomacher (the patterned, golden piece of fabric), pinned over a blue kirtle.
The black loop visible at the lady’s forehead is part of the hennin’s supportive construction and is probably attached to a headband.
later 15th century (ca. 1470)
Bibliothèque de Genève
Ms. fr. 189: Tristan en Prose
fol. 62r - Iseult learns of the marriage of Tristan andIseult Blanchmais (Isolde of the White Hands)
15th century (ca. 1470-1472) Southern Netherlands - Bruges
London, British Library
Harley 4380: Chroniques (Vol. IV, part 2) by Jean Froissart
fol. 106r
http://www.bl.uk/catalogues/illuminatedmanuscripts/record.asp?MSID=7232&CollID=8&NStart=4380
15th century (ca. 1470-1472) Southern Netherlands - Bruges
London, British Library
Harley 4380: Chroniques (Vol. IV, part 2) by Jean Froissart
fol. 6r - “marriage of Philip d’Artois and Marie, daughter of Duc de Berry”
http://www.bl.uk/catalogues/illuminatedmanuscripts/record.asp?MSID=7232&CollID=8&NStart=4380
15th century (ca. 1470-1472) Southern Netherlands - Bruges
London, British Library
Harley 4380: Chroniques (Vol. IV, part 2) by Jean Froissart
fol.189v - “landing of the Dame de Courcy at Boulogne”
http://www.bl.uk/catalogues/illuminatedmanuscripts/record.asp?MSID=7232&CollID=8&NStart=4380
Check out the peeking braies of the servant carrying the black chest!