The first bronze casting of Leonardo da Vinci's original "Horse and Rider" wax sculpture (Jolson PR)

A metal casting of a 504-year-old Leonardo da Vinci beeswax sculpture was unveiled to the world in a ceremony on Monday in Los Angeles. "Horse and Rider" is the only known three-dimensional piece of art created by Leonardo to still exist in the world and one of only about two dozen authenticated Leonardo works in the world today.

"It's a momentous occasion," Art Encounter's Rod Maly told Yahoo News before the unveiling at the historic Greystone Mansion in Beverly Hills. "The beeswax sculpture has been in private collections for nearly 500 years, so it has not been promoted. Nothing like this has ever happened in the history of mankind."

And in a development that is sure to intrigue historians and art fans alike, the sculpture is believed to contain a thumbprint of Leonardo.

The original beeswax sculpture measures 12 inches high, 12 inches long and 7 inches wide, and is believed to have been intended as the model for a much larger sculpture. The Renaissance military figure riding upon a horse was created in 1508 by Leonardo as a gift for his friend and benefactor, French military governor Charles d'Amboise. After Leonardo's death in 1519, the beeswax sculpture was given to his apprentice Francesco Mezi and is believed to have remained with his family in Italy until the 1930s when it was moved to Switzerland for safekeeping.

A thumbprint believed to belong to Leonardo Da Vinci (Eric Pfeiffer/Yahoo! News)

In 1985, American businessman Richard A. Lewis purchased the beeswax sculpture but says he wasn't aware of its historic value. "In all honesty, I was very naïve to what I had," Lewis told Yahoo News during an interview before the new bronze casting's unveiling. That same year, Lewis contacted Dr. Carlo Pedretti, widely considered the world's foremost living authority on Leonardo and professor emeritus of art history and the Chair of Leonardo Studies at UCLA. Dr. Pedretti studied and eventually authenticated the beeswax sculpture.

"For someone to call up and say 'I think I own a Leonardo da Vinci sculpture,' you're like yeah right, I'd like to put it next to my Mona Lisa," Brett Barney, president of the American Fine Arts Foundrytold Yahoo News. "But when he brought it in, right away we knew we had something."

Using what is called a "lost wax casting process," Barney and his team at the foundry spent three years working with the beeswax sculpture and eventually created a working mold from it. From there, a master bronze sculpture was created. In essence, they have created a new piece of authenticated work from one of the world's artistic masters, nearly 500 years after his death.

"It's the opportunity of a lifetime," Barney said. "To be part of a masterpiece by da Vinci himself, I can't think of anybody that would be more prestigious."

When the beeswax sculpture was studied in detail, it was discovered that along the horse's right breast a thumbprint exists. And while there is currently no way to verify, the print is believed to be Leonardo's.

The beeswax sculpture actually sat in Lewis' closet for more than 25 years before he contacted the foundry. And now, Lewis is determined to share the discovery with the world. And along with the piece's historic value, Lewis is using the unveiling for a good cause. Several hundred metal castings have been made from the newly created mold, which Art Encounter will make available to interested collectors. Lewis himself has committed to donating $1 million of the proceeds to the Salvation Army's substance abuse program.

"It is a magnificent piece of art and I'd like to have as many people as possible be able to appreciate it," Lewis told Yahoo News. He said he eventually plans to donate the original beeswax sculpture and master casting to a museum.

After its unveiling in Los Angeles, the new mold and master sculpture will be displayed in New York, London and Las Vegas, home to a new Leonardo exhibit at the Venetian Hotel.

The new "Horse and Rider" mold taken from Leonardo's beeswax sculpture. (Jolson PR)