It would have been easy to turn Livia into a grotesque caricature of unmaternal instinct. In a 1999 interview with Salon, David Chase, creator of "The Sopranos," said, "I saw actress after actress who just did not get it. Most of the time they were over the top, or played the Italian mother as very dramatic. Nancy just got it. She is a genius."

Marchand understood the source of the character's anger; Livia was a woman consumed by resentment over minor slights that went back 30 years. She was as driven by the Mafia's code of vengeance as her son was. And Marchand understood that for Tony's neuroses and guilt -- and hatred of her -- to ring true, she had to convey some of the screaming, spiteful mother she had been in his youth. Marchand played Livia as an echo of a harridan's shriek, a seemingly abandoned wasp's nest that people didn't want to get too close to. Her face was a subtly nuanced mask of wary-eyed misery and vindictiveness; her movements -- a dismissive wave of the hand, a self-pitying snort into a handkerchief -- were small and deliberate and calculating. And that voice! Livia didn't speak, she sneered, accused and belittled. (Her most famous line is "Oh, poor you!" snidely flung at her son after he tells her about his own miseries.)

The mean-spirited Livia was poles apart from Marchand's previous television role, as elegant, refined newspaper publisher Mrs. Pynchon on "Lou Grant." But it's a measure of her gutsiness and skill that you can't imagine another actress in either of these two roles. Marchand's career spanned more than 40 years. She was in the original TV production of Paddy Chayefsky's "Marty"; she performed in stage productions of Shakespeare, Chekhov, Shaw and Genet; her films ran the gamut from Merchant-Ivory's "The Bostonians" to the first "Naked Gun"; she won four best supporting actress Emmys for "Lou Grant" and a 1999 best supporting actress Golden Globe (and an Emmy nomination) for "The Sopranos."

When Marchand took the role of Livia, she made it clear to all concerned that she was battling cancer, as well as chronic obstructive pulmonary disease, but Chase and HBO took a chance on her anyway. Livia was supposed to have died at the end of the first season, after putting out a hit on her own son. But her character proved so popular that Chase wrote her into the second season. Bedridden after suffering a stroke (or maybe she was just pretending), Livia appeared sparingly; it was clear from her frailty in the last few episodes that Marchand's condition had worsened.

Thematically, it made sense that Livia's screen time, and her physical strength, should be diminishing; Tony had confronted her -- had intended to suffocate her, actually -- at the end of the first season. The second season was about how Tony tried to convince himself that her power over him was waning. "She's dead to me," he said over and over, obviously unconvinced. It's unclear how Chase will deal with Marchand's death next season. But Marchand took an amazingly good-humored approach to the bittersweet confluence of her role of a lifetime and her life-threatening illness. "If I die, it's not my problem," Marchand told Entertainment Weekly earlier this year. "It's David left holding the bag."

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