By Eric Pfeiffer | The Sideshow

Fiona McLaren, 59, had kept an old painting in her Scottish farmhouse for decades. She reportedly didn’t think much of the painting, which had been given to her as a gift by her father. But after she finally decided to have the painting appraised, some experts are speculating that it may in fact be a 500-year-old painting by Leonardo da Vinci and potentially worth more than $150 million.

"I showed it to him [auctioneer Harry Robertson] and he was staggered, speechless save for a sigh of exclamation," said Ms. McLaren, according to The People.

Indications of a da Vinci: 1. A similarity between the boy and child in his famous piece Madonna of the Rocks, 2. A distinctive ’v’ shape in the middle of the woman’s hairline reminiscent of that shown in the last supper, 3. The fleur-de-lys is often said to be a hidden emblem of the secretive Priory of Sion, 4. The area by the woman’s shoulder is unfinished, common in da Vinci works, 5. A tracing of the figure in the Last Supper matches exactly the outline of the woman in this painting, 6. The baby’s second toe is longer than the big toe - another classic da Vinci feature.

Old document: On the back of the 500-year-old painting is a document which is believed to be a papal bull - order of the Catholic Church. On it the word ’Magdalene’ can be seen.

Ms McLaren said her father used to call the painting ’Madonna and Child with John the Baptist, but having spent a decade researching the history of the work, the nurse believes the painting is actually not the Virgin Mary with baby Jesus, but Mary Magdalene and her son.

She thinks the true meaning of the artwork may have been disguised for centuries because such a work would have been considered heretic by the Roman Catholic Church.

The Pope decreed the Virgin Mary should be illustrated in blue whereas Mary Magdalene had to be shown in red attire, as depicted in this painting.