White Duchess  1795  https://en.wikipedia.org/wiki/The_White_Duchess

   The Black Duchess 1797 the subject of the painting is Maria Cayetana de Silva, 
   the 13th Duchess of Alba, then 35 years old. 
   It is a companion piece to the more chaste The White Duchess, completed two years earlier.

Duchess of Alba

 
   Heard an interesting story about the Duchess of
   Alba, Goya painted her picture in the nude
   and the Duke heard about it and was coming to
   Goya's studio to see the painting, so Goya stayed
   up all night, painting a second painting of the
   Duchess, same position, only with clothes on.
   when he finished both paintings he had the two
   canves framed as one, with the nude behind the
   clothed one and sent to the Duke.  When the Duke
   died, they revealed the existence of the hidden
   painting, today both hang in the Praedo in Spain.

  FANDANGO - Luigi Boccherini   Fandango

I found the film clip to be fascinating,  a visual ballet, no dialogue, only looks and gestures
in the Prado in Madrid Spain
Goya and Duchess of Alba, two paintings:  La maja vestida  and  La Maja desnuda 
The identity of the model and that of the commissioner have not been confirmed. 


Spanish Art History Site  <-- lots of ads !