NEW YORK - The 85-year-old son of philanthropist Brooke Astor was sentenced yesterday to one to three years in prison for exploiting her mental frailty to plunder her millions, but the legal saga surrounding the society doyenne's fortune will persist with planned appeals.

Anthony Marshall showed little emotion as state Supreme Court Justice A. Kirke Bartley sentenced him to the minimum term his conviction required for looting the fortune of his mother, who gave away nearly $200 million to institutions and charities before she died at 105 in 2007.

Marshall will remain free for at least the next month as his defense lawyers try to persuade an appeals court to let him remain free on bail during the appeals process.

The judge noted Marshall's World War II service and the possibility that Astor herself would have been aghast to see her only child imprisoned, but he said the law left him no choice but to impose a prison term.

"It is a paradox to me that such abundance has led to such incredible sadness," Bartley said. He gave Marshall until Jan. 19 to provide his medical information to prison officials and otherwise prepare for time behind bars.

Marshall declined to speak at his sentencing. Prosecutors described him as an unrepentant thief who deserved punishment. Defense lawyers portrayed him as a dutiful son who believed his mother wanted him to have the money and items he was convicted of stealing.

Co-defendant Francis X. Morrissey Jr., 67, an estate lawyer convicted of helping Marshall steal his mother's money, was also sentenced to one to three years in prison. Like Marshall, Morrissey will remain free until Jan. 19 and is planning to appeal.

Marshall faced up to 25 years in prison after being convicted of 14 counts, including grand larceny and scheming to defraud. Defense lawyers have said his myriad illnesses would make any prison term a virtual death sentence.

Meanwhile, a fight over Astor's estate that was on hold during the criminal case goes on in civil court, pitting Marshall against several charities. Citing that fight, Bartley turned down prosecutors' request to force Marshall to pay more than $12 million as restitution.