Relatives were cleaning out the basement of a recently departed member of the family when they came across a small, dirty painting. They took it with other items to an auction house who said it would probably sell for between $600 and $800.
But two French art dealers recognised it immediately and put in an opening bid of $250. The pair went on to buy the painting for $870,000 after competing with another two European dealers who also knew its worth. They could tell by comparing the exotic costumes of the subjects of other Rembrandt paintings.
It's tiny, just 9 inches square and he named it The Unconscious Patient, painted around 1624. It's part of a set of five works depicting the five senses and shows two men trying to revive a young man with smelling salts.
It will be on display at J. Paul Getty Museum in California from today, 11 May 2016.
After restoration, the monogram 'RF' in the upper left corner was revealed which stands for 'Rembrandt Fecit' or 'Made by Rembrandt'. He would have been around 18 years of age when he painted it.
It was later sold to billionaire collector Thomas Caplan for an undisclosed amount.
In 2009, a Rembrandt sold at auction for a record breaking $43 million.