This tumblr aspires to become a helpful resource for history (and mainly fashion history) research and focuses primarily on illuminations from medieval and renaissance manuscripts.
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!
The woman appears to be wearing a style of headdress nowadays referred to as “St Birgitta’s cap”. It is famously and often depicted in Maciejowski Bible, for example here and here.