Curator John Elderfield and the daughter of artist Richard Diebenkorn were among the first witnesses called by the plaintiffs to testify in the Knoedler & Company forgery trial Tuesday afternoon. The trial, which began this week in United States District Court in Manhattan, hinges on whether or not Ann Freedman, Knoedler’s former president, knowingly sold a fake Mark Rothko painting to the collectors Domenico and Eleanore De Sole for $8.3 million in 2004. The two allege that Freedman misrepresented the work while aware of its inauthenticity, and are suing Freedman, as well as the gallery and its holding company, 8-31 Holdings, for $25 million in damages.

The trial shines a light on the scandal that brought down what was once the oldest gallery in New York City, and one of the most prestigious. Knoedler had been open for 165 years until closing abruptly in 2011. News eventually surfaced that the gallery had sold, over the course of 14 years, some 40 fakes attributed to Abstract Expressionist painters, including Richard Diebenkorn, Robert Motherwell, Jackson Pollock, and Mark Rothko. All of these works had come to Knoedler by way of a Long Island dealer named Glafira Rosales and, allegedly, her co-conspirators, Jose Carlos Bergantinos Diaz (Rosales’s boyfriend) and his brother Jesus Angel Bergantinos Diaz. Authorities have argued that the fakes were executed—in many cases with a meticulous eye for detail—by Pei Shen Qian, a Chinese immigrant living in Queens. Rosales pled guilty to federal tax evasion and money laundering charges in 2013. The Diaz brothers, who have been charged with conspiracy to commit wire fraud and money laundering, were arrested in Spain in 2014; they are still awaiting extradition. Qian, who has also been indicted, fled to China and has maintained that he did not know that his works were being sold as authentic pieces.

Freedman and her lawyers deny that she was aware the paintings were fake, claiming that she went out of her way to authenticate the Rosales works and that she—as well as a number of art world experts, including David Anfam, the author of the catalogue raisonné of Rothko’s works on canvas—were convinced by the forgeries. At one point, according to her lawyers, Freedman exchanged a genuine Rothko from her personal collection for one of Rosales’s fakes, which she then hung in her apartment for the next 15 years.

Before Elderfield took the stand, Freedman’s lawyers made their opening arguments, which included a brief art history lesson on Abstract Expressionism. “It was emotional,” Freedman’s lawyer, Luke Nikas, said of the style. “It was abstract.”

He then listed off the personal vices of this generation of painters, citing Pollock’s alcoholism and Rothko’s suicide to make the argument that the group on a whole was “highly dysfunctional,” and hardly concerned with keeping detailed records of their work and business transactions. (This point was presumably hammered home by a brief clip from the 2000 film Pollock, which was projected on a screen for the ten-member jury to see. Ed Harris, starring as the titular artist, is seen trading a painting for food at a grocery store, then sloppily drinking a beer while riding his bike. “He’s drinking in the middle of the day,” Nikas noted.)

Elderfield is the chief curator emeritus of painting and sculpture at the Museum of Modern Art in New York. He looked the part, wearing a gray three-piece suit and large spectacles. (On the stand, Elderfield, who worked as a curator at MoMA for 30 years until retiring in 2008, played down his current honorary title, saying that it had no benefits beyond a MoMA admissions card.) He was soft-spoken to the extreme, so much so that a sizable portion of the court room let out a frustrated murmur when he began talking because no one could hear him. Throughout his testimony, the stenographer asked him to repeat himself (at one point Elderfield had to spell out the name Paul Cézanne, the subject of a recent class he taught at Princeton) and one of Freedman’s lawyers interrupted the questioning to say he couldn’t hear. A bailiff finally went and adjusted Elderfield’s chair, placing him closer to the microphone.

Elderfield was called to testify about two fake Diebenkorn paintings—the first forgeries that Rosales brought to Knoedler, in 1994, and which the gallery subsequently sold. Rosales claimed they were from the artist’s “Ocean Park” series, his best-known work, made between 1972 and 1976, and named for the location of his studio at the time.

Elderfield told the jury his personal history with Diebenkorn: as a young man, he had written a review of one of the artist’s exhibitions in 1971, and Diebenkorn wrote to Elderfield personally inviting him out to the West Coast. Elderfield described a professional friendship that lasted until Diebenkorn’s death in 1993. Elderfield curated an exhibition of the artist’s works on paper at MoMA in 1988, during which time he visited his studio and spent several days looking at the work he had there. He described all of the works being meticulously archived.

Gregory Clarick, a lawyer for the plaintiffs, projected images of the Rosales Diebenkorn paintings. Elderfield described seeing them at Knoedler, in a February 1994 show about “unexhibited works” from the “Ocean Park” series. He said he looked at the paintings with Phyllis Diebenkorn, the artist’s widow, whom he accompanied to the exhibition. “My reaction was that they were very dubious,” Elderfield said. “I felt that they were…not done by the artist whose work I had seen very extensively.” He said they appeared to be “mechanical,” as well as “bland and flat.” Elderfield claims he told Freedman right away of his suspicions, to which she allegedly responded, “They’re from a good place. I don’t see any problem with these.” Elderfield testified that Freedman wouldn’t say where the paintings had come from.

“I felt I was not convinced these were works by Diebenkorn,” Elderfield said. “I didn’t come flat out and say these were fakes, because you have to rely on more than first impressions.” But, he said, he’s found that “first impressions are not necessarily wrong ones.”

During cross examination, Nikas introduced a letter into evidence. It was dated September 5, 1995, and typed out on Knoedler letterhead, addressed to Diebenkorn’s widow and daughter. The letter seems to refer to the fake Diebenkorn works that had been on view at Knoedler. But, according to the letter, Elderfield, along with Diebenkorn’s widow, had “deemed them to be attributable to Richard Diebenkorn.” Elderfield said this was “not an accurate representation of what happened.”

Later in the afternoon, Diebenkorn’s daughter, Gretchen, would testify that both she and her mother had expressed doubts to Freedman about the Diebenkorn works on view at Knoedler in 1994, but that when they received this conflicting letter, neither responded to it.

“My mother would not let me,” she told the court.