She was almost certainly the last link to New York’s Gilded Age, reared in Beaux-Arts splendor in a 121-room Fifth Avenue mansion awash in Rembrandt, Donatello, Rubens and Degas. Her father, a copper baron who once bought himself a United States Senate seat as casually as another man might buy a pair of shoes, had been born before the Mexican War. Her six siblings died long before her, one in the 19th century.

Though she herself lived into the 21st century, Huguette Clark managed through determination and great wealth to spin out her golden childhood to the end of her long, strange, solitary life. Mrs. Clark died on Tuesday, at 104, at Beth Israel Medical Center, the Manhattan hospital where she had chosen to live in recent years, said Michael McKeon, a spokesman for Mrs. Clark’s lawyer, Wallace Bock.

In retrospect, Mrs. Clark’s life opens a portal onto the city’s glory days of Astors, Guggenheims and Vanderbilts, for the Clarks once walked among them. More recently, however, thanks in large part to her singular efforts to avert the limelight, the family name has faded from view.

By all accounts of sound body and mind till nearly the end of her life, Mrs. Clark had lived, apparently by choice, cloistered in New York hospitals since the late 1980s. There, first in Doctors Hospital and later at Beth Israel, she was reported to have lived under a series of pseudonyms. (The most recent, MSNBC.com, said Tuesday, in reporting the news of her death, was Harriet Chase.)