Bruegel, Courtauld Gallery

Think of 16th century Netherlandish painter Pieter Bruegel the Elder and you'll probably think of peasants in landscapes. Swilling ale, breaking bread, napping under a tree, stealing a kiss in the corner: earthy, folksy scenes. Or perhaps you think of his macabre allegorical engravings, such as The Seven Deadly Sins, full of grotesquerie and lumpen forms, giving off more than a whiff of Bosch.

Either way, the Bruegel we know and love is rambunctious, earthly - a bit coarse, even. What a revelation, then, are his three surviving grisailles. There is a stillness, refinement and purity to these austere scenes. They demand silence and prolonged contemplation: so far from the bustle of his instantly-gratifying genre paintings.

Grisailles are monochrome paintings in shades of grey, which were hugely popular as altarpieces in 16th century Flemish art. Bruegel's panels, though, constitute one of the earliest and rarest examples of independent cabinet pictures in grisaille, created for private contemplation and enjoyment. They are rarefied and mysterious, the hushed spectral figures look like marble sculptures.

Other grisailles will be accompanying the panels, so visitors will get a good idea of the development of this Northern European genre. But even if the show consisted of the three panels alone, it would be a triumph. They really are exquisite.