London, Dec 19 (ANI): Three previously unknown drawings have been discovered on the back of one of Leonardo da Vincis major works.

Sylvain Laveissiere, a curator, spotted the almost invisible sketches on the back of Vincis famous work The Virgin and Child with Saint Annewhen it was taken down in September for restoration.

He took notice of some grey marks, resembling a horses head and a human skull, which had previously been dismissed as stains.

And he was proved right after the painting was photographed with an infra-red camera at the Centre for Research and Restoration of the Museums of France.

The wood, on which the work was mounted, contained an 18cm by 10cm (7in by 4in) equine head and a 16.5cm by 10cm skull, in black stone or charcoal, complete with orbital and nasal cavities, jaw and teeth.

Surprisingly, the camera disclosed a third drawing, a 15cm-high infant Jesus with a lamb, which was invisible to the naked eye.

According to a spokeswoman for the Louvre the discovery was amusing and moving as well as it was mysterious, since the drawings appear to have gone unnoticed for 500 years.

They were not meant to be kept. They had been largely wiped out, which explains why no one had spotted them until now, Times Online quoted Bruno Mottin, of the Louvres art laboratory as saying.

The Louvre claimed that there was evidence to suggest that the sketches, in black stone or charcoal, were indeed made by Vinci himself.

Were being very careful, but what is troubling is the similarity with drawings that are already known, said Vincent Pomarede, head of paintings at the Louvre.

He said that Vinci might have used the back of the painting to practice on.

The skull resembles those in Leonardos other sketches, and the horses head is reminiscent of those in The Battle of Anghiari, a lost masterpiece known only because it was copied.

The baby Jesus looks like a draft for the figure in The Virgin and Child with Saint Anne.

It would be quite typical of his working style for him quickly to sketch out ideas that came into his head on whatever paper or, in this case, panel was to hand, said Jill Burke, an Italian Renaissance specialist at Edinburgh University.

The Louvre said that it would carry out tests to try to confirm the identity of the author. (ANI)