Until last week.
On Wednesday evening, Lazarus arrived in Philadelphia from Paris in a great green crate. On Friday morning, in a ground-floor gallery of the academy's Hamilton Building, where a Tanner retrospective will open Saturday and continue through April 15, the crate's sides were unbolted, the foamcore pads were removed, and, for the first time, American light fell directly on the American masterpiece.
Anna O. Marley, the academy's curator of historical American art, clasped her hands in expectation. Gale Rawson, senior registrar, leaned forward.
"We've looked at images so long as we prepare for the exhibition, when they come out of the crate, it's like Christmas," Rawson said. "Anna says it's like seeing an old friend."
Marley, curator of the exhibition, which is the first comprehensive retrospective of Tanner's career in 20 years, likened the moment to "30 Christmases."
The painting, she noted, won a great prize at the 1897 salon, which propelled Tanner to the heights of cultural celebrity.
"This painting, after it won the prize, was spread across the New York Times, it was in the Chicago newspapers, it was written about all over the country," she said. "It was so celebrated."
Even so, Tanner made only a few brief visits back to Philadelphia and America after achieving such fame. He remained an expatriate, living largely in France for the next four decades until his death in 1937.
Tanner was a sensitive and deeply religious African American who sought refuge in Europe from the racial indignities rampant in his homeland.
Marley directed attention to the original back of the painting. There, near the edges, are stickers from the 1897 salon (Lazarus was Painting 259) and a label from the Musée du Luxembourg, which identifies Tanner simply as an artist of the "école Americaine" - the American school.