A pair of Rembrandt portraits, the last known to be in private hands, sold for more than £11 million ($14 million) at Christie's in London on Thursday.
The sale comes nearly 200 years after they first went under the hammer at the auction house.
The paintings date from 1635 and had been expected to fetch between £5 million and £8 million as part of Christie's "Old Masters" sale.
The auction house said the hammer eventually came down at £11,235,000.
The 20-centimetre tall oval portraits depict an elderly plumber named Jan Willemsz van der Pluym and his wife, Jaapgen Carels.
The couple, painted in an unusually intimate style for Rembrandt, were friends of the artist's family and came from his home town of Leiden in the Netherlands.
Henry Pettifer, international deputy chairman of Old Master paintings at Christie's, told AFP in Amsterdam last month that he was "stopped in his tracks" when he first saw the portraits.
"I was really staggered to discover that the pictures had never really been researched and never been addressed in any of the literature on Rembrandt over the course of 200 years," Mr Pettifer said.
An ancestor of the current owners bought the paintings at auction at Christie's in 1824, where they were listed as Rembrandts, and they have remained in the same collection ever since.
"They've been sitting quietly and enjoyed by the owner's family over the course of two centuries … rather casually enjoying them very much," Mr Pettifer said.
After discovering them, forensic work began to verify that they were genuine Rembrandts, including scientific analysis by art experts from Amsterdam's Rijksmuseum.
The paintings are the smallest known portraits by the 17th century Dutch master, who was better known for much larger works commissioned by wealthy families.
