A Pennsylvania museum has agreed to sell a 16th century portrait that once belonged to a Jewish family that was forced to part with it while fleeing Nazi Germany before World War II.

The Allentown Art Museum will auction “Portrait of George the Bearded, Duke of Saxony,” settling a restitution claim by the heirs of the former owner, museum officials announced Monday. The museum had bought the painting, attributed to German Renaissance master Lucas Cranach the Elder and Workshop, from a New York gallery in 1961 and had displayed it ever since.

The portrait was owned by Henry Bromberg, a judge of the magistrate court in Hamburg, Germany, who had inherited a large collection of Old Master paintings from his businessman father. Bromberg and his wife, Hertha Bromberg, endured years of Nazi persecution before leaving Germany in 1938 and emigrating to the United States via Switzerland and France.

“While being persecuted and on the run from Nazi Germany, Henry and Hertha Bromberg had to part with their artworks by selling them through various art dealers, including the Cranach,” said their lawyer, Imke Gielen.

The Brombergs settled in New Jersey and later moved to Yardley, Pennsylvania.

Two years ago, their descendants approached the museum about the painting, and museum officials entered into settlement talks. Museum officials called the upcoming sale a fair and just resolution given the “ethical dimensions of the painting’s history in the Bromberg family.”

“This work of art entered the market and eventually found its way to the Museum only because Henry Bromberg had to flee persecution from Nazi Germany. That moral imperative compelled us to act,” Max Weintraub, the museum’s president and CEO, said in a statement.

The work, an oil on panel painted around 1534, will be sold in January at Christie’s Old Master sale in New York. The museum and the family will split the proceeds under a settlement agreement. Exact terms were confidential.

One issue that arose during the talks is when and where the painting was sold. The family believed the painting was sold under duress while the Brombergs were still in Germany. The museum said its research was inconclusive, and that it might have been sold after they left.

That uncertainty “was the genesis of the compromise, rather than everybody standing their ground and going to court,” said the museum’s attorney, Nicholas M. O’Donnell.

Christie’s said it would not be ready to provide an estimate of the portrait’s value until it could determine attribution. Works by Cranach — the official painter for the Saxon court of Wittenberg and a friend of reformer Martin Luther — are generally worth more than those attributed to Cranach and his workshop. Cranach’s portrait of John Frederick I, Elector of Saxony, sold for $7.7 million in 2018. Another painting, attributed to Cranach and workshop, sold for about $1.1 million in 2009.

“It’s exciting whenever a work by a rare and important Northern Renaissance master like Lucas Cranach the Elder becomes available, especially as the result of a just restitution. This painting has been publicly known for decades, but we’ve taken this opportunity to conduct new research, and it’s leading to a tentative conclusion that this was painted by Cranach with assistance from his workshop,” Marc Porter, chairman of Christie’s Americas, said in a statement.

The Bromberg family has secured agreements with the private owners of two other works. The family is still on the hunt for about 80 other works believed to have been lost under Nazi persecution, said Gielen, the family attorney.

“We are pleased that another painting from our grandparents’ art collection was identified and are satisfied that the Allentown Art Museum carefully and responsibly checked the provenance of the portrait of George the Bearded, Duke of Saxony and the circumstances under which Henry and Hertha Bromberg had to part with it during the Nazi-period,” the Bromberg family said in a statement.