Tantalising images and taboo themes, animal instinct and godly passions - Mary Russellon the hottest exhibition in London
Jupiter, in the guise of a swan, folds his dark wing protectively round the pale body of Leda while at their feet lie the cherubic infants just hatched from the egg which is the result of their coupling. And though Leda smiles sweetly, her head tilting away from her suitor and her hand repulsing the swan's long lascivious neck tells us that the god's continuing passion for her is not altogether welcome.
Intent on adopting as many disguises as was necessary, Jupiter was the most active of gods but it is as a swan that his lovemaking with Leda continues to intrigue. The two figure no less than three times at the Barbican's show Seduced: Art and Sex from Antiquity to Now, with Francois Boucher's painting the most revealing and Agostino Carracci's the most vigorous. The one described above is 17th century by an unknown artist, after Leonardo.
Call it what you will - eroticism, pornography, love, affection or plain old sex - a show which offers explicit images of this most absorbing of subjects will never be short of an audience.
However, this exhibition is not only a glorious celebration of the pleasures of the body but an examination of the way in which societies throughout the ages have dealt with an activity in which private pleasure and public morality are often at odds.
Within the framework of a respectable gallery, the naming of parts is acceptable with vulva and penis taking the female and male leads, while the anus and the nipple play strong supporting roles. But it's when we move outside this area of acceptability that cultural conditioning comes into play cloaking the genitals with tortuous euphemisms or salacious tags. Understandable, perhaps, in an area so uneasily charted.
In lovemaking, the borderline between passion and violence is sometimes blurred, the distinction between strength and dominance uncertain and that which is tolerated in the privacy of your own home, totally taboo outside it. At the Barbican, a variation on the confessional edict - if it wasn't fun, it wasn't a sin - is Tracey Emin's two fluorescent tube signs which read, "Is anal sex legal?" and "Is legal sex anal?"
TABOO, IN FACT, is something of a major player in this show and the first image the visitor sees is the plaster cast of the fig leaf covering the genitalia of Michelangelo's David, a copy of which is at the Victoria and Albert Museum. The leaf was made to spare the blushes of Queen Victoria when she visited the museum, though connoisseurs will be interested to know that the leaf is 18 inches long. At about the same time as it was being decorously positioned, the museum in Naples was busy concealing the great wealth of sexual images that had been uncovered in Pompeii. These were placed in the Reserved Cabinet in the city's National Museum in order to hide them from the innocent - defined as women and children - and from the corruptible, which included the illiterate working classes.
Until the middle of the 18th century, the classical period had been regarded as one of fine art and philosophising, but with the unearthing of Pompeii came the dreadful revelation that the Romans got up to all sorts of licentious behaviour both in and out of their bedrooms and had fun doing it, as illustrated by Le Gladiateur - a bronze image of a man hung about with bells trying to subdue his exuberant penis - though it seems that fun now has its limits, even in a one-time brothel.
Visiting Pompeii earlier this year and dropping by one of the famous lupercali (brothels), I joined some friends trying out a stone couch and was admonished by a guide for our frivolity: time had hallowed the house of ill-repute.
Another image from that period shows the divine Pan impregnating a goat - a reminder, whether we like it or not, of the animal side of our nature.
LUCKILY, THERE IS no Reserved Cabinet at the Barbican. The penis romps from room to room gloriously rampant, its tip occasionally taken between pursed lips or clasped by a firm male fist, possibly the owner's. Women pleasure themselves and each other or lie legs akimbo, the vulva red as lipstick and plump as a cushion with pubic hair delicately sketched in or left to flourish thick as undergrowth as artists, down the centuries, work through their own and society's dreams - the two sometimes at variance with each other.
Rembrandt van Rijn's etching of Jupiter as an old man uncovering a sleeping Antiope to peer in quiet if anticipatory delight at the shadowed secret between her legs is in contrast to his Monk in a Cornfield vigorously going about his unholy business with a woman while in the background a farmer unconcernedly scythes the long grass.
Western Christianity, of course, provided opportunity for religious chastisement - a gift to the fantasist - and there are images of a woman tied up by a tonsured monk and of a cleric in a state of arousal while whipping a very knowing female sinner.
But with 300 exhibits spanning 2,000 years it is difficult not to zero in on certain forms. One favourite is the stunning marble statue of Sleeping Hermaphrodite whose body has those most important of male and female attributes - breasts and testicles. Who could not want to stroke this perfect body simply because their own gender identity is challenged by its ambiguity? Look one way and it's a soft young man, another way and we see a gentle young woman. Art allows us appreciate both.
Another nude that catches the eye and indeed caught mine before I learned its story is Francois Boucher's Female Nude Reclining on a Chaise-longue, on loan from the National Gallery of Ireland. The soft glow of flesh, the model lying on her front, the cushions carefully arranged to raise her buttocks, all speak of anticipation. This is Louise O'Murphy, daughter of an Irish soldier and the person she is waiting for is Louis XV whose mistress she was - albeit one of many.
The theme of incest is represented by a painting by Simon Vouet of Lot, one hand on his daughter's breast while she drapes a bare leg across her father's thigh. Biblical scholars tell us that his daughters, thinking there were no more men left on earth, seduced their father in order to procreate and that, in any case - wait for it - he had drink taken. But that is not how the artist shows it. Lot, old but vigorous and looking decidedly sober, is clearly enjoying his daughter's body.
THE WHOLE SHOW is called Seduced: Art and Sex but the coupling of visual art and seduction is an idea that cannot go unchallenged for it does not permit of other possibilities. What of the seductive power of music, processed in that part of the brain for which there are no words so that we are left speechless? Or indeed what of words themselves? What of that ice-cold moment in Shakespeare's Richard III when the Lady Anne allows herself to be seduced by a man who sweet-talks her now but who will later destroy her? For myself, a few lines of poetry does the business - though don't tell anyone.
And what are we to make of the image of a medieval woman, her basket full of cut-off penises? Is she an irate, rejected woman? Or is she offering her wares as potent charms to aid pregnancy or as protection against it? Are the penises acceptable iconic offerings for her time? Our attitudes to sex is ever-changing, as are our chosen icons. When I removed my IUD - a state-of-the-art contraceptive device which served me faithfully - I sprayed it gold and wore it as an earring: an icon in its own right.
Seduced is a timeline of attitudes to sex and gender. Lavinia Fontana (her Portrait of a Nobleman can be seen in the National Gallery of Ireland) is here represented by an oil painting entitled Minerva in the Act of Dressing. Born in 1552, Fontana was unusual in that she painted nudes at a time when women were not supposed to know anything about bare flesh. She was later elected to the Academy of Rome. But it is the 17th century Japanese exhibits - women whose shoes and lips are as tiny as they are red, men with hands resting lightly on lovers' heads - which display an aspect of affection so often absent from the more robust western images.
So many images of one universal act, and as I handed back my cloakroom ticket, serendipitously I noticed its number: 69. Soixante-neuf - don't you just love it?
Seduced: Art and Sex from Antiquity to Now is at the Barbican, London, until Jan 27, 2008. See www.barbican.org.uk or tel: 0044-8451207550. Open to over 18s only. Entrance free but advance booking advisable as space is limited.