Identified as "18th century French cap with mourning crape" on a blog page about French Revolutionary-period mourning customs. http://www.blastmilk.com/personal-rambling/18th_century_mourning/ However, no source or provenance is noted. The black looks like ordinary silk ribbon, definitely not true mourning crape with its dull, diagonally crinkled appearance. Mourning crape was manufactured in the 19th c., but I'm not sure about the 18th. Does anyone have sources?