Astor matriarch's son goes on trial in New York

The son of Brooke Astor, matriarch of one of America's most storied and wealthy families, was accused in court Monday of a heartless plot to defraud the socialite in her final years.

Anthony Marshall, a World War II veteran and former US ambassador, leaned on his cane as prosecutors opened the high-society trial in New York.

He is accused of exploiting his mother's increasingly severe Alzheimer's condition to get her to change her will, securing for himself millions of dollars intended to go to charities.

Marshall, 84, and alleged accomplice Francis Morrissey, 66, "literally pulled Mrs Astor out of the arms of her nurse... and dragged her behind closed doors so she could change her will," prosecutor Elizabeth Loewy said.

Astor, who had married into the clan of business tycoons, was one of America's most beloved philanthropists and had given away approximately 200 million dollars to New York institutions before dying in 2007, aged 105.

She "lived by the saying that it is better to give than to receive," Loewy said, but ended up victim of "greed."

Marshall, who fought with the US Marines at Iwo Jima, argues he stole nothing from his mother and that she willingly gave to him. Morrissey, an estate lawyer, also pleads not guilty.

The courtroom on the 15th floor of a Manhattan courthouse will see a parade of celebrity witnesses during what's expected to be a lengthy trial.

Friends of Astor who could take the stand include former secretary of state Henry Kissinger, veteran TV presenter Barbara Walters, former UN chief Kofi Annan and the wife of designer Oscar de la Renta, Annette.

Marshall -- who faces up to 25 years in prison if convicted -- might also have to confront his own son in court.

It was Philip Marshall's legal challenge to his father's guardianship over Brooke Astor, who he alleged was being forced to live in squalid conditions, that set off the current court case.

As always, Marshall arrived in court supported by his wife Charlene. She came equipped with a special green cushion to protect her from the unforgiving wooden court benches.

Charlene Marshall is not charged, but prosecutors claim that she was a driving force behind Marshall's alleged campaign to secure more money from Astor.

Prosecutors say that Astor never approved of her son's marriage to Charlene, previously been married to a church minister, and planned to leave her little in her will.

"Anthony Marshall's preoccupation with getting money for Charlene was a motivation for the scheme to defraud," Loewy said.

"You will hear evidence that Mrs Astor simply didn't care for her, for Charlene," she added.