"Watteau's château"

•Concert Hall by Servandoni, master of trompe-l'œil and decorator of Saint-Sulpice, Paris's great 18th-century church

•Salon by Oudry, painter of the royal hunts - that is, the greatest animal painter of the time

The Marquis let Watteau store paints and brushes in this laundry room. He used the walls to experiment, painting one figure over another. Museums would be delighted to have this notebook, but it is part of the walls.

...as restorers peeled away the coverings with which 19th-century owners concealed works they viewed as frivolous - or openly licentious.

Placed in the most prestigious part of a salon, its coded message is typical of the art that nobles commissioned for their châteaux. A "W" may be Watteau's signature....