Nancy Marchand, the distinguished character actress who excelled at playing wise and imperious authority figures -- newspaper publishers, queens, grande dames and a madam -- and who achieved perhaps her greatest fame as the domineering mother of a mob boss in the television series ''The Sopranos,'' died on Sunday at her home in Stratford, Conn., one day short of her 72nd birthday. She also had a home in Manhattan.
Her daughter Katie Sparer Bowe said that no specific cause of death was given, but for several years the actress had been suffering from cancer and chronic pulmonary disease.
A wide diversity of playwrights -- among them Chekhov, Shaw and Shakespeare as well as Jean Genet, Paul Osborn and A. R. Gurney -- was within Ms. Marchand's range. She once described her physical presence as ''a strange combination of being very imposing and down-to-earth,'' an accurate assessment of the seemingly contradictory image she projected.
That description could be applied to the overburdened wife she played in the 1980 Broadway revival of Osborn's ''Morning's at Seven,'' the patrician publisher on the long-running ''Lou Grant'' television series and her portrayal of Livia Soprano, the monster mother of them all, a woman bred into the Mafia who without a blink of hesitation sets up her son Tony to be assassinated because he has moved her to a nursing home.
Except for her indomitability, Livia was in direct contrast to all the ''tasteful ladies'' Ms. Marchand played in her busy career. At 70, after more than 50 years of acting, she discovered a new popularity, and it was for playing a wildly unsympathetic character. Livia Soprano was a role that she compared to that of Caligula's great-grandmother in ''I, Claudius,'' a woman who also happened to be named Livia.
Throughout her career, Ms. Marchand gave her roles an unexpected edge. Even when her characters were at their most officious, they retained a measure of charm, and her more affectionate characters could also be sardonic. She was an expert at both light and more serious comedy, moving effortlessly from the outrageous antics in the movie spoof ''The Naked Gun,'' to Lady Bracknell in ''The Importance of Being Earnest.''
In plays like ''Morning's at Seven,'' she warmed an audience's collective heart, but she never wore her own heart on her sleeve, avoiding the cul de sac of sentimentality. Instead she was wily in performance, turning in an instant from comedy to poignance.
Often she acted onstage with her husband, Paul Sparer -- in everything from ''A Phoenix Too Frequent'' by Christopher Fry to Edward Albee's ''Delicate Balance'' to Mr. Gurney's ''Love Letters.'' Mr. Sparer also had his own rewarding career in plays that included Elie Wiesel's ''Zalmen, or the Madness of God'' and ''The Burnt Flowerbed'' by Ugo Betti. Individually and together they were ultimate theatrical professionals.
Mr. Sparer died in November. In addition to her daughter Katie, an actress who lives in Stratford, Ms. Marchand is survived by a son, David of Madison, Wis.; another daughter, Rachel Sparer Bersier, an opera singer of Manhattan; and seven grandchildren.
Offstage, Ms. Marchand was the reverse of so many of her strong-willed characters, a woman with a natural sense of insecurity, someone who felt uneasy in social situations. ''I'm always very uncomfortable with people.'' she once explained in an interview in The New York Times. ''It's something that I get upset with myself for, but that's the way I am. But I love people. And when I'm on the stage, I can embrace people and still feel safe. There are a lot of different facets to my personality that I don't use all the time in my house, or in everyday life, that I can experience and share when I'm on a stage.''