In July, auction house Christie’s will put up for sale two Rembrandt portraits that have been in the possession of one family in Britain for almost two centuries and were “unknown”.

Scholars were unaware of the Dutch master’s artworks until experts at the auction house identified them during a routine appraisal.

According to the Financial Times, the 1635 paintings depict a Dutch couple, Jan Willems van der Plem and his wife Japken Karls, a couple who had family ties to the artist.

These are early works of the painter, as they were created just as Rembrandt was beginning to build his reputation.

Although they are no more than 20 centimeters tall, the two paintings are estimated to sell for between five and eight million British pounds (about $6.2 million to $10 million).

The portraits will go on sale at Christie’s London showrooms on July 6, after being shown in New York and Amsterdam.