IN her heyday as the bejeweled empress of New York philanthropy, Brooke Astor entertained presidents, first ladies and a potpourri of pooh-bahs and literati at her elegant 14-room duplex on Park Avenue. And when she died on Aug. 13, 2007, at Holly Hill, her estate in Westchester County, at 105, she left behind two households’ worth of cherished possessions, including Qing dynasty lacquer furniture, a jade-and-diamond Cartier clock and dozens of 19th-century dog portraits.


Five years later, after a corrosive battle over her $130 million estate, Sotheby’s will auction 901 lots of furnishings, decorative art, fine art and jewelry on Sept. 24 and 25, to support causes Mrs. Astor championed during her life, like the New York Public Library, the Metropolitan Museum of Art, Historic Hudson Valley and the Animal Medical Center.


The auction follows a maelstrom of litigation that began in 2006, when her grandson Philip C. Marshall filed a lawsuit accusing his father, Anthony D. Marshall, her only son, of mishandling her finances and mistreating her. That dispute led to the father’s conviction in 2009 on charges of defrauding and stealing tens of millions of dollars from his mother, who was suffering from dementia. (Mr. Marshall, now 88, has appealed the verdict.)


The lavishly illustrated Sotheby’s catalog offers a glimpse of the genteel splendor in which Mrs. Astor lived at Holly Hill and at 778 Park Avenue, and sets the scene for the alleged depredations of her twilight years.


A stylish dresser and irrepressible flirt, Mrs. Astor loved elegant design with a touch of whimsy, and for several years worked as an editor at House & Garden. Later, as the wealthy widow of Vincent Astor, Mrs. Astor hired her friend the formidable decorator Sister Parish, who excelled at imbuing upper-class clients’ homes with impeccable taste, to design her Park Avenue apartment. Kenneth Jay Lane, another friend, observed: “It was an absolutely charming apartment. Everything was perfection. It wasn’t pretentious, just charming and comfortable.”


For the library, Mrs. Astor turned to Albert Hadley, Mrs. Parish’s business partner, who created one of the most admired interiors of the 20th century: a red-lacquered, brass-trimmed sanctuary that reflected Mrs. Astor’s starring role in reviving the fortunes of the New York Public Library. The room showcased leather-bound books that had belonged to Mr. Astor, the real-estate tycoon to whom she was married for more than five years before his death in 1959. And amid the chintz and gilded Buddhas, it was festooned with animal figures, a fanciful circus that included a carved-ivory Indian elephant studded with rubies and emeralds from Van Cleef & Arpels (lot 82, $6,000 to $8,000) and a Chinese gilt-bronze figure of a recumbent buffalo (part of lot 44, $2,000 to $3,000).


As the art historian John Richardson, a frequent guest of Mrs. Astor’s, noted, “Brooke was above all a great animal lover.”


Devoted to her dachshunds, Boysie and Girlsie, she took playful delight in sharing her love of dogs in particular.


Mr. Lane recalled, “I got the most marvelous gift from Brooke once: this little box arrived at my office and in it was a little Chinese jade dog. It came with a note saying, ‘Kenneth, it’s time you had a dog.’ ”


For nearly a quarter-century, beginning in the mid-70s, invitations to dine at Mrs. Astor’s Park Avenue apartment were among the most sought-after in New York. Acceptance into her circle of friends conferred the glow of social desirability and the privilege of mingling with the leading writers, politicians and philanthropists of the day. Barbara Walters, a close friend, remembered that “from the moment you came in, there was a sense of gaiety.”


“She was a great hostess, fun and lively,” she added.


After dining on Astor plates and monogrammed silver, guests would repair to the drawing room for coffee, where they could sit on Louis XV chairs festooned with floral chintz (lot 122, a set of four, estimated to fetch $12,000 to $18,000), amid old master drawings by Tiepolo and Boucher, and a Canaletto that once belonged to the Duc de Talleyrand (lot 143, $300,000 to $500,000).