Jan Brueghel the Elder and Joos de Momper

Two names over one picture here means two men genuinely painted it. In Antwerp around 1620 that was ordinary business, and the work was split along each specialist's trade. Joos de Momper, a landscape painter, laid in the countryside and the hazy violet-blue distance he was known for. Jan Brueghel, son of Pieter Bruegel the Elder and court painter to the Archdukes Albert and Isabella who governed the southern Netherlands, put in the people. He did the same service for his friend Rubens, adding flowers and small figures to Rubens's canvases.

The picture hangs in the Prado and is nearly two metres wide. A market is under way, and on the grass beside it women are spreading linen out flat. That is a bleaching field, where cloth was left in the sun for days to whiten, and Flemish towns kept open ground for the purpose.