Lot Essay
The Dutchman Guillermo Ducker (or Duker) worked in Madrid, mainly for the Spanish court and the aristocracy, notably the ducal family of Osuna. He was friendly with Goya. For further information, see M. C. Espinosa Martín, Iluminaciones, pequeños retratos y miniaturas en la Fundación Lázaro Galdiano, Madrid, 1999, pp. 224-225, and M. Tomás, La miniatura retrato en España, Barcelona, 1953, pp. 73-74.