History matters. As the people of memory, we revere history, and we resent when others seek to exploit or revise it. Nazi victims and their heirs rely heavily on history - and morality - to support their claims for artworks looted or lost during the Nazi era. More than six decades after the Holocaust, it is hard to make a legal claim for the artworks. These likely changed hands multiple times and moved across national borders, where the transactions were made under various legal systems. If a painting was in Germany in 1933, sold in Switzerland in 1936, transported to the US and later donated to a New York museum, which law applies? German? Swiss? American? There are no easy or obvious legal choices. Victims tend to make claims based on how - and when - they lost possession of the object, not how it was sold or moved once the prewar owner no longer had it. They argue that artworks were confiscated by the Nazis, or that they were sold under duress to earn funds to flee or to pay discriminatory taxes, or that they were displaced when Jews were deported to concentration camps. These are arguments based on history. The extended family of Paul von Mendelssohn-Bartholdy, of the German-Jewish dynasty, relied on history to argue that two Picassos were sold under duress during the Nazi era. The heirs sought the paintings from New York museums: Boy Leading a Horse was donated in 1964 to the Museum of Modern Art; the Solomon R. Guggenheim Museum received Le Moulin de la Galette in 1963. The two museums then filed suit in December 2007 to establish their ownership. This was a tricky case. The claimants had conflicting interests. Julius H. Schoeps is von Mendelssohn-Bartholdy's great-nephew and the director of the Moses Mendelssohn Center for European Jewish Studies in Potsdam. The other claimants, Edelgard von Lavergne-Peguilhen and Florence Kesselstatt, are the niece and adopted daughter of von Mendelssohn-Bartholdy's Aryan second wife, Elsa, to whom the paintings allegedly were given as a wedding gift in 1927. Schoeps contended that if, as alleged, von Mendelssohn-Bartholdy gave the paintings to Elsa, it was a pretext, conceived by Paul as he neared death in 1935, to protect them from seizure by the Nazis. It was a highly anticipated case in which interim court rulings were parsed like Talmud because the museums are prominent, the paintings are famous, the Mendelssohn name looms large and the legal issues were significant to Nazi victims, museums and art collectors. US DISTRICT JUDGE Jed Rakoff ruled in January that he would allow a jury trial because the claimants had presented "competent evidence" that von Mendelssohn-Bartholdy never intended to transfer his paintings, but was forced to do because of threats and economic pressures by the Nazi government. As the trial was to open in US District Court in Manhattan last month, the museums and claimants announced they had reached a settlement. There were no details, except that the museums would keep the paintings and that Schoeps, von Lavergne-Peguilhen and Kesselstatt would receive unspecified compensation. It is not unusual for settlements to remain confidential. But this was an important case that, in theory, could provide another avenue for people to pursue claims for paintings that were not confiscated but sold because of duress, and thus considered a forced sale. The heirs say they have done that, although that remains to be seen. The confidentiality of the settlement irritated the judge, who noted that the heirs had invoked "the weight of history on their behalf." It would be "extraordinarily unfortunate that the public would be left without knowing what the truth is," Rakoff said last month, giving them time to reconsider the confidentiality clause. The museums heeded the judge and agreed to disclosure. But not Schoeps, von Lavergne-Peguilhen and Kesselstatt. "The fact that the plaintiffs, who repeatedly sought to clothe themselves as effectively representatives of victims of one of the most criminal political regimes in history, should believe that there is any public interest in maintaining the secrecy of their settlement baffles the mind and troubles the conscience," Rakoff said in a ruling last week. THERE IS an unsavory sentiment in the art world that Holocaust-related claims are the tool of greedy relatives seeking to cash in on artworks that increased substantially in value since World War II. In this case, the museums originated their suit, in part, "to combat what they alleged, in effect, was an effort by plaintiffs and their counsel to use the facade of Nazi iniquities to extort monies from public institutions that were vulnerable to bad publicity," Rakoff wrote last week. The judge was clearly vexed by the legal precedents of his federal court circuit that barred him from making the settlement details public without everyone's consent. The plaintiffs remained opposed to disclosure, the judge wrote, "for reasons wholly unexplained and seemingly no more compelling than concealing the amount of money going into their pockets." The heirs "have claimed loudly throughout that they were vindicating a historical injustice," Rakoff wrote, saying he hoped the plaintiffs would "reflect on their public responsibilities." To this end, the heirs issued a statement saying they "view Judge Rakoff's several rulings as vindicating their claims and as an unqualified success." This is an overstatement. Rakoff's rulings permitted the case to proceed. "The claim by the heirs was never just about money, but primarily about securing justice for Paul von Mendelssohn-Bartholdy," Schoeps wrote. This is not good enough. As Rakoff said, "The court finds the confidentiality provision of the settlement agreement and the plaintiffs' objection to disclosure to be against the public interest and a troubling reversal of the parties' previously stated positions on this issue. From the outset, the parties on both sides portrayed this lawsuit as of considerable public interest because of the importance of establishing the truth concerning the sensitive issues involved." Justice demands disclosure. In the last decade, museums have faced enormous pressure to reveal the provenance of the works in their collections and for transparency in their research. Two important New York museums agreed to disclose the settlement terms concerning two Picassos. It is the heirs who tied the judge's hands. Without public disclosure, a cloud hangs over the history of von Mendelssohn-Bartholdy's Picassos, and makes this an unfortunate historical moment: when the heirs took advantage of the restitution environment created by others, without regard to how their private interests could harm communal ones. The impression is that these claims are indeed about money, and transparency is one-sided. The venue - the court - was chosen by the museums. But the claimants, by making their case in public and wrapping themselves in history to stake that claim, incurred a public responsibility to reveal all.