In order to track the etymology of different headgear terms I wound up in some lovely sites for tracht worn now. But I’ve lost them all. I’m sure I saw pieces of a hauben on a frame that included breaks in the pattern to allow the back to fold in without losing so much work. It might be in my 9thC folder but I suspect I just didn’t save information thinking I’d find it more easily when I wasn’t tired.
Part of the reason I am doing this is because pattern shapes, support layers, materials, decoration really don’t offer clues as to what an item will be called unless you happen to know for sure via a dictionary of the time. But they do help identify time and place if there is a decent record and solid provenances for extant items.
I may have to start putting quote marks around the terms when I use translation software as this etymology issue means modern dictionaries can be very imprecise.