Helmsley died of heart failure at her summer home in Greenwich, Conn., said her publicist, Howard Rubenstein.

Already experienced in real estate before her marriage, Helmsley helped her husband run an enterprise that included managing the Empire State Building.

She became a household name in 1989 when she was tried for tax evasion. The sensational trial included testimony from disgruntled employees who said she had terrorized the help and the executives at her hotels and homes.

That image of Helmsley as the "queen of mean" was cemented when a former housekeeper testified that she heard Helmsley say: "We don't pay taxes. Only the little people pay taxes."

Helmsley denied having said it, but the words followed her for the rest of her life.

In the tax case, the couple was accused in state and federal indictments of charging millions of dollars in personal expenses and home improvements to their businesses. She was convicted in federal court in 1989 on 33 federal tax evasion counts and sentenced to four years in prison.

In 2007, Forbes magazine ranked her as the 369th richest person in the world, with an estimated net worth of $2.5 billion.

"She was an extraordinary woman who clearly knew what she believed in and was determined to do what she thought was the right thing to do," said Steven Spinola, president of the Real Estate Board of New York. "She was extremely smart, determined and willing to come up with opinions and make decisions."

The Helmsleys' residences included a nine-room penthouse with a swimming pool overlooking Central Park atop their own Park Lane Hotel; a 28-room estate in Connecticut; a condo in Palm Beach; and a mountaintop hideaway near Phoenix. She flew the globe in the couple's 100-seat jet with a bedroom suite.

But her detractors said she nickel-and-dimed merchants on her personal purchases and stiffed contractors who worked on her Connecticut home. It was tips from disgruntled employees led to the tax-evasion charges.

When her husband died in 1997 at age 87, Helmsley said in a statement: "My fairy tale is over. I lived a magical life with Harry."

She was 51, with the looks of a former model, when she married Harry Helmsley in 1972. It was her third marriage.

She was already a successful seller of residential real estate in a hot New York market. He was 63, one of the richest men in America.

In 1980 he made her president of Helmsley Hotels, a subsidiary which at the time operated more than two dozen hotels in 10 states.

For the better part of a decade, a glamorous Leona Helmsley smiled out of magazine ads dressed in luxurious gowns and tiara, advertising that the Palace was the only hotel in the world "where the Queen stands guard."

On July 4, 1976, Harry Helmsley lit the Empire State Building in red, white and blue — a tribute not to the Bicentennial, but to his wife's birthday, he said. It cost $100,000 — "less than a necklace," he said.

But the Helmsleys' charmed life ended in 1988 when they were hit with tax-evasion charges.

Harry's health and memory were so poor that he was judged incompetent to stand trial. His wife, after an eight-week trial, was convicted of evading $1.2 million in federal taxes by billing Helmsley businesses for personal expenses ranging from her underwear to $3 million worth of renovations to the Dunellen Hall estate in Connecticut.

Sentenced to four years in prison, she tried to avoid jail by pleading that Harry might die without her at his side. Her doctor said that prison might kill her because of high blood pressure and other problems. At a March 1992 hearing, the judge rejected that argument and even ordered her to surrender on April 15 — tax day.

Helmsley served a total of 21 months and was released in 1994.