NEW YORK - The 85-year-old son of philanthropist Brooke Astor was sentenced yesterday to as many as 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 one to three years in prison - the minimum term his conviction required - for looting his mother's fortune. She gave away nearly $200 million to institutions and charities before she died at age 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 stay free on bail indefinitely while his planned appeal plays out.

The judge noted Marshall's World War II service and the possibility that the late Astor herself would have been aghast to see her son imprisoned, but he added that 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," said Bartley. He gave Marshall until Jan. 19 to provide medical information to prison officials and otherwise prepare for life behind bars.

Marshall declined to speak at his sentencing, at which prosecutors described him as an unrepentant thief and his lawyers strove to portray him as a dutiful son who believed that his mother wanted him to have the money he was convicted of stealing.

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

Marshall faced as many as 25 years in prison after being convicted of 14 counts, including grand larceny and scheming to defraud. His mother was suffering from Alzheimer's disease when she died.

In the final year of her life, a nasty family feud over her care was splashed all over the city's tabloids - including allegations that she was forced to sleep in a torn nightgown on a couch that smelled of urine while subsisting on a diet of pureed peas and oatmeal. Those allegations were never substantiated.