Advanced new x-ray reveals Rubens' sensual secret

A new discovery, just revealed, suggests that Peter Paul Rubens was every bit as sensual as his famous fleshy nudes. In 1638, the Flemish artist made a full-length portrait of his second wife Helena Fourment. Wearing little more than a fur coat draped around her waist, she stands on a red rug against a dark background, and shows off her breasts and delightfully dimpled knees. The painting was affectionately titled Het Pelsken ("The Little Fur").

It has long been viewed as an intimate study of the woman Rubens married in 1630 following the death of his first wife, Isabella Brant. Further investigation, however, reveals that it was even more intimate than previously thought. An ma-XRF (macro x-ray fluorescence) scan, recently developed at the University of Antwerp, shows that Rubens painted over the right-hand section of his picture so as to conceal a surprisingly risqué symbol of sexual fulfilment.

It was apparent from an earlier x-ray that there was a sculpted lion's head to Helena's right, but the latest investigation has identified for the first time a statue of a peeing boy above it. Water spurted simultaneously from the lion's head and the little boy's penis.

It may not look much to modern eyes. There is, after all, a similar sculpture of a peeing boy, the Mannekin-Pis, in Brussels, which residents habitually dress up in a variety of different costumes. In the context of 16th- and 17th-century painting, however, the "puer mingens" was a well-known symbol of eroticism.

Researchers Katlijne van der Stighelen, Geert van der Snickt, Gerlinde Gruber and Koen Janssens, two of whom performed the x-ray, point out in a piece describing the discovery and its significance that the peeing boy appeared in bacchanalian paintings to illustrate lack of control, as well as in erotic contexts to suggest sexual union. Renaissance artist Lorenzo Lotto portrayed Venus reclining in the nude as Cupid urinated through a wreath into her lap. It doesn't require too great a leap of imagination to see how a boy shown releasing his fluid "transcended the limits of early modern decorum".

The academics surmise that Rubens became embarrassed by how sexually explicit his composition had turned out, and, losing his nerve, painted over the boy. The double-fountain was on a panel Rubens added specially to the picture as he extended it into a full-length portrait. The x-ray also shows that, as he did so, he peeled back the fur coat – which might have been his – to reveal more of his wife's naked body.

Perhaps it was her knowledge of what lurked beneath the paint that led her to change her mind over who should inherit the picture. Having initially stipulated that it should go to Jan-Baptist van Brouchoven van Bergeyck, whom she married after Rubens died in 1640, she eventually left it to her children by Rubens, the man who wed her, 37 years his junior, as a ravishing girl of 16.

Stighelen et al's description of the discovery appears in "Rubens in Private", a new book edited by Ben van Beneden and published by Thames & Hudson on 6 July.