Two paintings lost for years at the hands of the Nazis have found their way into the Yale University Art Gallery.

Last month, the gallery became the only museum in the United States with two paintings by the late Gothic artist Meister der Heiligen Sippe, known also as the Master of the Holy Kinship, after it acquired two of his six panels from a 16th-century altarpiece in Germany.

In 2003, the paintings, which the Nazis forcibly acquired in 1936, were returned to Robert and Virginia Stern, the heirs of the family from which they were taken, according to a gallery press release.

The Sterns offered the paintings to the gallery as a partial gift, and the gallery announced its acquisition last month, said Laurence Kanter, the gallery’s curator of early European art.

Kanter said Robert Stern had been trying to recover the panels for many years, until they were restored to him in 2003, so he could make them accessible to the general public.

“[He was] hoping that he would be able to place them in an American institution where they would be freely available to the public and, ideally, used by students on a regular basis,” Kanter said in an e-mail. “I suggested to him that I thought Yale would suit his needs perfectly, and as one of his sons [Adam Stern ’82] is a Yale alumnus, he readily agreed.”

The acquisitions, which are currently on display as part of “Art for Yale: Collecting for a New Century,” are part of a six-panel altar piece. They are now the earliest examples of German painting in Yale’s collection.

One of the panels depicts Saints James the Greater and John the Evangelist, and the other depicts Saints Philip and James the Lesser.

Kanter said Sippe is one of the best representatives of his schools of art.

“German painting of his period is exceptionally rare,” Kanter said. “The Cologne school, of which [Sippe] is a representative, is perhaps the most refined type of German painting of [the late 1400s and early 1500s].”

As a curator, Kanter said he recognized the interest of the museum in obtaining such pieces, which rarely come up on the market at prices the gallery can afford.

Frederick Ilchman, assistant curator at the Museum of Fine Arts in Boston, said that the MFA also has a piece of the altar and that such pieces are exceptionally rare.

“Many American collectors seemed to be more interested in painters from Flanders than in Germany,” he said. “The majority of these objects are located in museums in Germany that will presumably hold onto them, so it is very lucky that Yale was able to acquire these pieces now.”

The paintings’ history and the complicated process by which they eventually ended up in Yale’s collection add to their interest and significance, Ilchman said.

Yale University Art Gallery Director Jock Reynolds said in the release that the pieces are important for both their art historical and symbolic meanings.

“They are valuable not only for their intrinsic quality, their historical importance, and the contributions they will make to teaching at the gallery, but also as symbols of the most positive outcome in the cause of the restitution of works of art stolen during World War II,” he said.

History of Art professor Jacqueline Jung, who teaches a class on medieval European art and architecture, said she had not known of the acquisition but was thrilled that paintings by the Master of the Holy Kinship are now in New Haven.

“I have some familiarity with this artist’s work from my travels in Germany,” she said in an e-mail. “I do think it’s tremendously exciting to have these works here and will look forward to integrating them into my teaching wherever possible.”

The Sterns donated the works “in honor of all the families in Europe who were dispossessed during the Holocaust,” according to the release.