Study of a Horse with a Rider topped Sotheby’s old master evening sale on January 25 - the centrepiece of New York's old master week.

The early 1600s work sold for $5.1m – demolishing its $1.5m high estimate.

Worth $14,000 before the discovery (left), and $5.1m after (right)

The sale price is the result of a remarkable story of discovery.

Until recent months the piece had been attributed to a follower of Sir Anthony Van Dyck.

It sold for just $14,000 at Christie's last year, after which its new owner removed considerable overpainting and the background (a later addition) to reveal the true authorship: Sir Peter Paul Rubens.

It constitutes a rare study of an animal by Rubens.

This week's old master sales demonstrate the continuing rise of Rubens in the art market in recent years.

Yesterday's auction follows the strong $1.5m sale of a Rubens drawing at Christie's on Tuesday – doubling its $700,000 valuation.

The Master of the Innocents achieved a Rubens record £49.5m ($76.5m) in 2002.

There were two new artist auction records on the night. William Drost's Flora achieved $4.6m against a $600,000 valuation, while Adam de Coster's A Young Woman Holding a Distaff Before a Lit Candle doubled it valuation to make $4.9m.

"This market understands and appreciates a masterpiece when it sees one," commented Christopher Apostle, head of New York's old master paintings department.

Orazio Gentileschi’s Head of a Woman achieved $1.8m. The 1630s work is one of two known panel paintings by the artist. Gentileschi produced it while working at the court of England's Charles I. 

In January 2016, his Danae (1623) masterpiece sold for $30.5m.

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