Nearly half a century ago, the Rosenbach Museum and Library began building a relationship with the young author and illustrator Maurice Sendak, who very quickly started using the townhouse museum on Delancey Place as a repository for his original drawings, manuscripts, proofs, and rare editions.

Through the years the numbers mounted, and today about 10,000 items of Sendakiana, from original artwork to finished editions, fill the Rosenbach - the museum's best calling card with generations that grew up with his books.

But now that card is being recalled. Sendak never gifted the original artwork for Where the Wild Things Are and thousands of other items to the Rosenbach, and the trustees managing his legacy - he died at 83 in 2012 - have asked that the Sendak Collection be returned to them, ending a bond between artist and institution that many assumed would continue in perpetuity.

According to his will, filed in Fairfield County, Conn., Sendak instead chose to leave the collection to his eponymous foundation, which is expected to establish a museum and study center in his home in Ridgefield, Conn.

For the Rosenbach, Sendak represented a rare opportunity to speak to many constituencies simultaneously, and Pierre, Little Bear, and Max have become nothing less than the museum's personification. Characters from Chicken Soup With Rice, In the Night Kitchen, and Where the Wild Things Are have marched through a colorful parade of exhibitions that began in 1976 and have continued every two to four months. Since 1970, the Rosenbach has curated at least 72 Sendak shows.

But the Sendak trustees have served notice that they are exercising an option in a 1969 agreement between the author and the Rosenbach to reclaim all items owned by the estate - 98 percent of the Sendak collection housed at the Rosenbach. Sendak items will begin the migration to Connecticut in October in a process that may continue through the end of the year, said Rosenbach director Derick Dreher.

The Rosenbach houses 10,200 original and printed pieces owned by the Sendak estate. The museum owns about 600 other original and printed pieces, which will remain in Philadelphia, says Patrick Rodgers, curator of its Maurice Sendak Collection.

'Huge loss'

Sendak's drawing power was cited as a major asset in the 2013 merger of the Rosenbach and the Free Library of Philadelphia, and leaders planned to mount major shows at both the library and what is now called the Rosenbach of the Free Library.

The Rosenbach had long hoped that Sendak might leave his work to it.

"The agreement allowed him great freedom, but we hoped to earn his trust and loyalty, and the hope was that a collection would be there permanently," said Kimerly Rorschach, director of the Seattle Art Museum, who was a curator at the Rosenbach in the 1980s. "It's a huge loss. I am sorry about it for Philadelphia and the Rosenbach. I can see the charm of having it at his house. I've visited, and it's an enchanting place. But it won't be so easily accessible."

Free Library president and director Siobhan Reardon said that while she puts the collection in the "very nice to have" category, "it's not the be-all and end-all of the total Rosenbach collection. We still have plenty to collaborate over. We probably have one of the best Beatrix Potter collections, [Robert] Lawson, [Arthur] Rackham, never mind all of the important works by [Oscar] Wilde, [William] Blake, and on and on. Realistically, we would never be able to build a museum dedicated to Sendak the way the executors want to."

Still, as libraries grasp for relevance, losing Sendak - whose dark messages and acid social commentary arrived in the homes of millions, safely cloaked like so many kiddie-book Trojan horses - is a blow. Dreher says that for anyone who thinks of libraries as dusty old places, Sendak was a "threshold breaker."

A first visit

The author's will, however, hardly overlooks the Rosenbach. He directed his executors to give the Rosenbach his vast collection of rare-edition books, including works by Herman Melville and Henry James; his collection of correspondence by others, including Mozart, the Brothers Grimm, and Melville; and select articles from his Mickey Mouse collection. The Rosenbach is unsure how many items it will eventually receive, but already hundreds have arrived, with more on the way.

Sendak found the Rosenbach in 1966 when a librarian at the Free Library pointed it out as a place that might slake his thirst for James, Melville, Blake, and James Joyce. He developed a deep affection for the collection left by brothers Philip and A.S.W. Rosenbach. As his own career developed - not to mention his own wealth - he became a major collector in his own right.

In addition to books and other items, Sendak's passing triggered the payment of a $2 million bequest from his estate to the Rosenbach. This was in addition to a $1 million gift he made earlier. Sendak's gifts, plus $2.5 million from Frederick R. Haas, have helped to bring the endowment to a current market value of $7.7 million. The Rosenbach's Maurice Sendak Building retains its name.

The right of the Sendak estate to recall the collection is not in dispute; his will makes clear his wish to leave to his foundation "all of the works of art created by me for my books and all materials related thereto, including, without limitation, manuscripts, dummies, sketches of and for my books, changes to and proof sheets for my books, and all related ephemera."

The will is also clear about the museum in his Ridgefield home: "It is my wish that the Maurice Sendak Foundation Inc. operate said property as a museum or similar facility, to be used by scholars, students, artists, illustrators and writers," and be open to the public.

But a paragraph in the will also directs the estate and Rosenbach to continue to work together, leaving open the possibility for Sendak material to travel back to Philadelphia on loan.

"We are not getting out of the Sendak business," Dreher said, though he concedes exhibitions will be much less frequent.

Donald Hamburg, a lawyer who is Sendak's executor and a trustee of the foundation, said: "We hope to work out an arrangement that would be satisfactory." He declined to answer a number of questions about a prospective Sendak museum, calling plans "a work in progress," though he said it would be an institution geared more toward "scholars and artists" than members of the general public.

Dreher called the Sendak works owned by and remaining at the Rosenbach "valued parts of the collection," but the Chertoff Mural - Sendak's only mural - may not stay. "It may be that removing the mural from the Rosenbach and lending it to the Free Library of Philadelphia will help us share this work with a larger audience," Dreher said.

But while the Rosenbach is handing over Sendaks, the Sendak estate is also handing over some treasures to the Rosenbach. During a recent interview at the museum, Dreher pulled out one gift from the Sendak estate: a copy of William Blake's Hayley's Ballads thought to be hand-colored by Blake himself. Other Blakes, too, have arrived from the estate. "We had a very good collection of Blake, he had an outstanding collection of Blake - now we have serious critical mass," Dreher said.

Also new to the Rosenbach from Sendak's rare-book collection are nearly four dozen Melvilles, including Timoleon (1891), published just a few months before the author died, in an edition of only 25 copies with Melville's signature on the title page, and a rare copy of Clarel, often considered to be the longest poem in American literature. "This makes the Rosenbach's Melville collection likely the best in the world," Dreher said.

Resonance between Sendak's own rare-book collection and the Rosenbach's is no coincidence. "He came and fell in love with the place," said Dreher, pointing out that Sendak first visited in 1966, only 14 years after A.S.W. Rosenbach's death. "It was a quirky place. He would nap on the beds. He had unparalleled access to a collection that interested him tremendously. He was essentially a 19th-century man born in the wrong century. He loved Brahms, Schubert, Melville. All this was manifested in the collection, and he was enchanted."

Other bequests

Sendak may have been enchanted, but there was a degree of pragmatism at work. He placed his first items with the Rosenbach in 1968, before his major fame and during an era in which illustrators were more often thought of as lower-caste creatures than pure artists. "There's no way a major museum would have been interested in his materials at that time," Dreher said.

Among Sendak's other bequests are the set and costume designs for operas, plays, and ballets to the Pierpont Morgan Library, and his fine-art photographs to the Metropolitan Museum of Art. The walking sticks that had once belonged to Peter Rabbit author Beatrix Potter and her husband go to London's Beatrix Potter Society.

The will directs that some of his properties, including a Fifth Avenue co-op, be sold. Other properties, plus $2 million, was willed to his friend and neighbor Lynn Caponera (one of three trustees of his estate), with the remaining assets - plus rights and royalties to his works - going to support the Sendak Foundation.

Other friends are provided for. His partner of more than 50 years, psychiatrist and art critic Eugene Glynn, died in 2007.

Whatever anyone is able to see and learn at a Sendak museum in Connecticut, certain insights into Sendak the man will not be among them. The first directive in his will after asking that his finances be settled was this: Noting that he had already shown his executors the location of "all of my personal letters, journals and diaries," he ordered them, upon his death, to be destroyed.

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