recently sold by Sotheby's for $4,850,000, even though the artist is something of a theoretical construct. It is titled A Young Woman Holding a Distaff before a Candle, but that is an invention of the auctioneers.
Anyway this is a fascinating detective story, and only one of many: there are hundreds of unsigned paintings of this period, and a thousand disputes about their origin. I think the core paintings in the Adam de Coster group make sense as the work of one man, and de Coster seems a plausible candidate. But whoever painted it, A Young Woman Holding a Distaff is just a glorious painting, and I think it is wonderful that it has been brought out of obscurity and revealed to the people of the world.