Stockholm's Royal Swedish Academy of Fine Arts is seeking a benefactor who will buy its most famous painting and leave it hanging in the National Museum.

The academy is offering Rembrandt's The Conspiracy of the Batavians under Claudius Civilis for 300 million kronor ($48.7 million Cdn), a discount from the $120-million estimated value of the painting.

The terms of the sale are steep, however: the painting must remain at the National Museum in Stockholm.

"It has hung at the National Museum since 1866," said Olle Granath, permanent secretary of the Royal Swedish Academy of Fine Arts. "That's where it's going to stay."

The sale is intended as a fund-raiser for the academy, which needs cash for the upkeep of its headquarters in downtown Stockholm, a 19th century building that requires a lot of attention.

Rembrandt painted The Conspiracy of the Batavians in 1661-62 on a commission from the city of Amsterdam, which ordered a series of paintings to mark the end of the Eighty Years War in which the Dutch battled for their independence from Spain. The Batavians, a Germanic tribe who conspired against the Romans, were believed to be forefathers of the Dutch desire for independence.

The original painting was about five metres square and included a cathedral-like frame around Rembrandt's rendering of the Batavians, led by the one-eyed Civilis.

The city appears to have sent the painting back to Rembrandt for revision and never reclaimed it. The artist cut out what remains — a closer focus on the Batavians painted with his usual attention to light.

The fragment is known to have been in Sweden since 1798 when it was donated to the academy "for eternity" by noblewoman Anna Johanna Grill.

The academy has a sizeable art collection as each new academy member must donate a work of art when joining it.