Jan Steen, 'An Interior with a Man offering an Oyster to a Woman', probably 1660-5

Centre stage, against a shadowy, mostly black-and-white background, the bright red jacket inevitably draws our eyes to the young woman. She leans back – rather immodestly, a glass of wine held in her lap, knees apart, one foot up on a box – and smiles directly up at the man offering her an oyster.

This not a polite gesture of thanks for the offer of a canapé to go with her wine. In seventeenth-century Holland, the connotations would have been understood immediately. Oysters were regarded as both an aphrodisiac and a reference to female sexuality: the man’s offer is an erotic advance. The woman’s response – implied in her pose, her direct glance and the fact that she is drinking alcohol, which was another well-known aphrodisiac – suggests complicity.

The closer we look, the more evidence we can find for this interpretation. The box on which the woman rests her toes is actually a foot-warmer – we are being led to imagine heat rising beneath her skirts. Right next to her, skulking under the table, a cat, a traditional symbol of lust, is licking out an oyster shell. In fact, there are oysters all over the place, empty shells scattered on the floor, and two men chat conspiratorially while one of them prepares another plateful. The curtains behind them are actually the drapes around a bed – a common piece of furniture in Dutch living rooms, but with more obvious connotations here. If you look closely in the shadows you can see that the table is supported by carvings of naked women, draped with garlands.

Given what else is going on, we would probably be safe to assume that the conversation between the young woman standing by the bed and the man with the hat is likely to be contractual in nature. The setting is a brothel; the two women work there.

Why would a rich Dutch merchant – the most likely customer for a painting of this type – want to hang such a painting in his elegant townhouse? This was a society in which religious devotion was considered extremely important, where promiscuity among respectable people would have been roundly condemned. Jan Steen was himself a lifelong Catholic, who also made religious paintings.

But this was also a society with a sense of humour – as we can tell from its taste in art. People may not have approved of such behaviour, but they saw its funny side and they enjoyed laughing about it. Steen was a master of comic innuendo and the most successful artist of his time at making obscene visual jokes. This scene was popular enough to have been repeated at least once. Another version of it is now in the National Gallery, Oslo; a third is also said to have existed.