Joachim Wtewael's Mars and Venus Surprised by Vulcan set a new world record for the artist at Christie's Old Master & British Paintings Evening Sale in London on July 3.
The previously forgotten copper panel, which the Dutch Mannerist created in 1610, sold for £4.6m ($7.3m), 15.8% above its $4m estimate.
In doing so it trumped the previous record for the artist of $6.2m, set by the oil on copper work Adam and Eve at Sotheby's in 2011, representing a 17.2% rise for his world record in a year.
Last night's piece, discovered among the property of a French noble family during a Christie's valuation, was said by the auctioneer to embody "the full scope of Wtewael's accomplishment".
It last changed hands in the mid 19th century.
A major surprise and a further artist world record was set by Pietro Lorenzetti Christ between Saints Paul and Peter. The 14th century work sold for £5.1m, more than trebling its £1.5m pre-sale high estimate.
Georgina Wilsenach, the head of old master and British paintings at Christie's London, commented: "This evening we… saw the market for Old Masters continue to break boundaries. This evening's sale went on to attract buyers from 22 countries in four continents, many of whom were new to this category, and some whom were new to Christie's altogether."
The sale also featured Rembrandt's A man in a gorget and cap, which sold within estimate for £8.4m, while the auction's top lot was John Constable's The Lock, which set a new record for the artist of £22.4m.
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