The Saint Birgitta’s Cap is the name commonly given to a white linen cap/coif seen on women in medieval art from approximately 1250-1500 across much of mainland Europe. This style of cap is named after the extant reliquary cap of St. Birgitta of Sweden currently held in the Marie Refuge Convent.
I teach a make-and-take class on a simplified version of this cap (no embroidery) and the handout can be found here: St. Birgitta Cap Class Handout
Photo: Isis Sturtewagen, Medieval Clothing and Textiles Vol. 4, Fig. 6.2
I made a simple version of the St. Birgitta Cap without the central lace or embroidered band. The cap is great if you don't have time or the hair length to do a period style.
The cap also makes a great base for other head coverings such as hats and veils. Veils don't really suit me, but hats do!
Photo by S.L. Rowe (https://www.flickr.com/people/140105642@N08/)
Photo by Nick Ferris, Photographer, Verily (http://jennieandnick.com/photography)