A painting bought by the National Gallery of Victoria in 1965 has been revealed as being the work of famed Renaissance painter Dosso Dossi.
Furthermore, the ABC reports the subject of the 16th century portrait is Lucrezia Borgia, one of the most infamous women of the Italian Renaissance.
She was the daughter of Rodrigo Borgia - the powerful Renaissance Valencian who later became Pope Alexander VI - and his mistress, Vanozza dei Cattanei.
The ABC reports the Borgia family epitomised ruthless politics and sexual corruption. History records Borgia as a manipulative woman who participated in incest and sexual orgies with her father and brother.
NGV conservator Carl Villis says it has taken years of research to unravel the mystery and it's believed to be the only formal painted portrait of Lucrezia Borgia.
If the painting is accepted for what the gallery believes it to be, he says it will it will be "highly-significant because it will be incredibly rare."
Gallery staff will not speculate on how much the painting could be worth.