An 11-inch bronze sculpture said to be linked to Leonardo da Vinci sits in a bank vault on Manhattan’s Upper East Side. “Horse and Rider” carries an estimate of $30 million to $50 million and is being offered for sale at the Pierre Hotel in New York this month, according to Guernsey’s auction house. But not everyone is convinced of its da Vinci origins. Dozens of similar bronzes already exist, raising more questions about whether the one hitting the auction block is truly unique.

The work depicts a nobleman on a bucking horse -- purportedly da Vinci patron Charles d’Amboise, a French governor of Milan -- in full military regalia. It was cast in 2012 with a mold taken from a beeswax model created more than five centuries ago, according to Guernsey’s. While the original’s current whereabouts are a mystery, late da Vinci scholar Carlo Pedretti, who wrote scores of books on the Italian Renaissance master, examined it in 1985, around the time it was made.