A painting by Leonardo da Vinci discovered at an estate sale sold privately in May 2013 for between $75 million and $80 million.

Sotheby's handled the private sale and details have been kept quiet until this week when insiders revealed that the transaction took place. The buyer still remains anonymous.

"Salvator Mundi," a circa-1500 image of Christ holding a crystal orb, was owned by a consortium of dealers that included New York-based Robert Simon and Alexander Parish. In 2012, the Dallas Museum of Art raised millions of dollars in an attempt to buy the rare oil-on-panel, but its efforts were rebuffed.

Layers of overpainting caused the painting to be misattributed as a copy after Boltraffio, who worked in Leonardo's studio. New research and analysis by Simon and others identified the painting as by the master himself, and it was subsequently included in "Lenoardo da Vinci: Painter at the Court of Milan" at London's National Gallery in November 2011 to February 2012.

The painting once belonged to England's King Charles I.