He amassed a massive private art collection from his Philadelphia penthouse. Now it’s for sale.

Sidney Rothberg was a soldier the first time he encountered priceless art.

Europe had been looted during World War II, and fences sold masterpieces on Paris street corners for cigarettes and panty hose. Rothberg, who grew up humble in Philadelphia and Atlantic City, did not purchase the pilfered treasures. But the beauty he beheld in them sparked a lifetime of insatiable curiosity about artists and their influences.

By his death in 2008, at the age of 83, Rothberg, a successful commodities trader, had amassed a renowned private collection, one that spanned centuries, styles, and mediums. He hung it all on the walls of his Fairmount penthouse.

Now, Rothberg’s family is offering some of those works for sale.

Beginning Feb. 27, the Freeman’s | Hindman gallery and auction house in Center City will host a two-day sale of nearly 250 works from Rothberg’s collections. Titled, “What Do You See?” The Collection of Sidney Rothberg, the show highlights the collector’s diverse taste and discerning eye. Ranging from French impressionism to European surrealism to 1960s New York avant-garde, the sale includes works from artists like Pierre-Auguste Renoir, Alexander Calder, and Georges Seurat. Many of the pieces have been privately held for decades.

“This is an international event,” said Raphaël Chatroux, head of American Art at Freeman’s | Hindman. “These works have not really seen the light of day for the last 40, 50, or even 60 years.”

The sale follows successful exhibitions in Paris, New York, and Chicago — select pieces will remain on exhibit at Freeman’s | Hindman’s until the auction — and represents a homecoming for an art collection built and curated in Philadelphia.

While attending Wharton after the war, Rothberg first pursued his new passion by poring over books he found in the research stacks of the Free Library. Later, he studied at the Barnes Foundation, eventually becoming a guest lecturer, and was heavily influenced by his friendship with longtime curator Violette de Mazia.

“This is a Philadelphia collection,” Chatroux said. “These are important names and great artists that are internationally renowned, and they have been kept in Philadelphia for a very long time.”

Rothberg’s daughter, Saranne Rothberg, the consignor of the collection, said that after so many years, she felt it was time to share the masterpieces she had grown up with.

“I felt we had a responsibility not to covet it,” she said of the collection.

For her, the sale symbolizes a personal remembrance of a passion that her father made sure to share. The show’s title is taken from the question Sidney Rothberg always asked his daughter and granddaughter when viewing a new piece of art: “What do you see?”

It was a question he posed to everyone who entered the house, from distinguished art collectors to delivery men. He hung precious art at toddler height so his daughter could see it better during his tea parties.

“We would sit on the floor, and he would tell me about why this piece was important in history, and how it was connected to art and what was happening in the world,” said Rothberg, a stage IV cancer survivor and founder of the nonprofit ComedyCures. She is donating a portion of the show’s proceeds to American Association for Cancer Research.

She can remember playing on the loading docks of the old Freeman’s auction house when she was still in nursery school and her father, a single dad, bid on new pieces. When she was 4, he let her do the bidding herself, reminding his daughter not to jump in too early.

“I raised my hand and bought my first painting,” she said.

Sidney Rothberg hung his collection — which grew to include antiquities, jewelry, glass, and ceramics — in every room, and on every inch of wall, in his home.

“Floor to ceiling, wall to wall, closets, and even from the ceiling,” said Saranne Rothberg. “Everywhere he could possibly study a work.”

For her father, every piece of art was a story to be explored. A story of technique and palette, subject matter, and medium. Most importantly, of those critical inflection points in an artist’s life when they dared to try something new.

“My dad loved experimentation and risk,” she said. “He collected those moments when artists were experimenting and then becoming the great artist they were. He would then compare this artistic inflection to other, better-known works, and excitedly track down who or what influenced that shift.”

The Rothberg collection is rife with those moments of discovery. There’s Renoir’s Head of a Boy in a Sailor Suit, a portrait the artist painted in 1885, just as he was becoming more stylized and searching for a solution to impressionism. And both Richard Diebenkorn’s painting, Girl in Tiled Room, and an untitled watercolor by British artist Chris Ofili, highlight Rothberg’s eye for spotting early work of rising stars.

“It’s interesting because at the time that he bought some of these works, the market was not so much in favor of these artists or those works,” said Chatroux. “But right now, enough time has passed [and] they are considered major.”

On sale day, Chatroux expects the Philly auction house to be full with bidders — and that others will be joining online from all over the world.

And although her father remained private about his collection during his life, Saranne Rothberg believes that he would be happy that the collection he built was now being shared. That he’d ask those experiencing it anew that same question he always posed: “What do you see?”

Select pieces from the collection are on exhibit at Freeman’s | Hindman, 2400 Market St., Feb. 16 - 26, 2024. Free.