An international legal drama that pits two of the world’s biggest art buyers against each other -- New York billionaire Leon Black versus a member of Qatar’s royal family - - was caused by sibling rivalry between Pablo Picasso’s grandchildren, according to the latest claims in the dispute.

The parties are fighting over Picasso’s 1931 plaster “Bust of a Woman,” depicting the artist’s then mistress and muse, Marie-Therese Walter. For years it was a prized possession of Maya Widmaier Picasso, a daughter born of the artist’s affair with Walter. Now, even as it sits on public display at the Museum of Modern Art in New York, no one can agree on who its rightful owner is.

Lawsuits, including one filed against art dealer Larry Gagosian, Apollo Global Management’s Black, and Picasso’s granddaughter in Manhattan court Wednesday, offer competing versions of events leading up to MoMA’s display of the sculpture. Court papers filed in other legal actions in Geneva and Paris also expose the details of transactions that are typically tightly guarded by parties to the opaque, high-end art market.

Picasso’s granddaughter, Diana Widmaier Picasso, convinced her mother to sell the sculpture for $106 million to Gagosian in 2015, according to Wednesday’s lawsuit. Gagosian was planning to resell the work to Leon Black, the chief executive officer of Apollo, a New York-based buyout firm, according to the complaint.

But the work was already in contract to be sold, according to Pelham Europe Ltd, the party that filed the lawsuit and claims to have rightful ownership of the work.

Sister Learns

Pelham, an agent for Sheikh Jassim bin Abdul Aziz Al-Thani and the Qatar Museums Authority, agreed to buy the work for 38 million euros ($47.4 million at the time of the sale in 2014) from Maya in a deal that was negotiated by her son, Olivier Widmaier Picasso, according to the complaint. They didn’t tell Maya’s daughter Diana about the agreement “to avoid the anticipated entreaties” that it be sold to her long-term ally Larry Gagosian, Pelham claims. When Diana learned of the sale to Pelham, she sought to repudiate it -- which her mother did, on the eve of the last of three installment payments, according the suit.

The siblings’ “competing curry for their mother’s favor and fortune” is to blame for the breach of contract, Pelham’s complaint said, adding that by acting as Gagosian’s agent, Diana got a lucrative commission.

Pelham seeks damages, a declaration that Gagosian and Black are not the owners of the sculpture, and the return of the artwork. Black should have conducted due diligence on the provenance of the Picasso sculpture, Pelham said in the suit.

Gagosian, his gallery, Picasso’s granddaughter and Black didn’t return calls and e-mails seeking comment. In a Jan. 13 statement responding to an initial lawsuit filed by Gagosian over the sculpture, Maya Widmaier Picasso contested Pelham’s claim, saying any allegation it wasn’t properly acquired by Gagosian is false.

“Windfall”

Gagosian, which sued Pelham in January over the dispute, claims Pelham paid too little for the sculpture, generating a "windfall" of more than $60 million at the expense of Picasso’s daughter and granddaughter. Gagosian said it had already entertained several $100 million offers for the work during its 2011 show, “L’Amour Fou,” which exhibited the work alongside other art inspired by Picasso’s affair with Walter.

Gagosian received title to the work on Oct. 2, per his sales agreement, according to his suit.

Black, a masterpiece hunter and MoMA Co-Chairman, is one of the world’s top 200 art collectors, according to ArtNews magazine. He bought Edvard Munch’s “The Scream" for $120 million in 2012. In 2009, he paid $47.6 million for Raphael’s chalk drawing “Head of a Muse.” His collection, valued at $800 million, represents 20 percent of his $4 billion net worth, according to the Bloomberg Billionaire Index.

Guy Bennett, the principal of Pelham, is currently the chief of Collections and Acquisitions of the Museums Authority of Qatar, according to court papers. In 2015, Qatar Museums, according to widespread reports, bought Paul Gauguin’s “When Will You Marry?” for $300 million, the highest price ever paid for a work of art.

Two casts of “Bust of a Woman” already exist -- one bronze, another cement -- according to Werner Spies’ catalog of 664 sculptures by Picasso completed between 1902 and 1971.

When the plaster bust is deemed sold, it will likely become the most expensive Picasso sculpture to change hands. Today that record rests with the bronze head of a woman that fetched $29.2 million in 2007 at Sotheby’s, according to Artnet.

The case is Gagosian Gallery Inc. v Pelham Europe Ltd. 16- cv-00214. U.S. District Court, Southern District of New York (Manhattan).