Why Peggy Guggenheim’s heirs should keep their hands off her collection

Despite what the great collector’s relatives are saying in a legal proceeding, her intimate museum in Venice is one of the wonders of the modern art world – and has in no way betrayed her joyous vision

The 10 best art patrons

As a new show at the National Gallery explores the influence of Paul Durand-Ruel, the dealer who ‘made’ the impressionists, Rachel Cooke highlights other great patrons and collectors