Once sold to Catherine the Great of Russia by his grandson, 70 paintings from Sir Robert Walpole's art collection have returned to the positions they occupied in the great Palladian house built to house them.
The exhibition is a tour of the mind of an 18th-century connoisseur. Paintings compete with furnishings, tapestries, carved sconces.
A portrait by Godfrey Kneller of John Locke, his head made all the more magnificent by the huge flurry of his wig, hangs above the fireplace. Perhaps the greatest work is a monumentally still Holy Family by Poussin, which seems to look forward to Picasso's 1920s classical nudes. This is a show of museum quality.
01603 598640; houghtonhall.com, to 29 September