Margaretta Large Fitler was born in Bryn Mawr, Pa., on June 9, 1926, one of two children of Margaretta Large Harrison Fitler and her first husband, William Wonderly Fitler Jr., a yachtsman and heir to an $8 million cordage fortune. A scion of Main Line privilege, Happy — she acquired the nickname for her sunny disposition — was a descendant of Gen. George Gordon Meade, who commanded Union forces at the Battle of Gettysburg. She and her brother, William, were often left in charge of servants, and her parents divorced when she was 10. She was a popular but indifferent student at the Shipley School in Bryn Mawr. After graduating in 1944, she became a wartime driver for the Women’s Volunteer Service in Philadelphia. She made her debut in 1946 and married Dr. Murphy two years later. They had four children, three of whom survive her: James B. II, Margaretta M. Bickford and Carol M. Lyden. The fourth, Malinda M. Menotti, died in 2005. Mrs. Rockefeller is also survived by her sons with Mr. Rockefeller, Nelson Jr. and Mark, and 14 grandchildren. Dr. James Slater Murphy, a boyhood chum of Mr. Rockefeller’s brother David, followed his father, Dr. James B. Murphy, a renowned cancer researcher, into the Rockefeller Institute in New York in 1950. He became a noted virologist there. The Murphy and Rockefeller families were neighbors in Manhattan, had summer homes in Seal Harbor, Me., and shared social orbits. The Murphys even built a home near the Rockefeller estate, Kykuit, at Pocantico Hills, overlooking the Hudson River in Westchester County. In 1958, Mrs. Murphy became a volunteer in Nelson Rockefeller’s first campaign for governor. After his election, she became his confidential secretary — and, later reports said, his mistress. After Mr. Rockefeller’s death, Mrs. Rockefeller and her sons gave up the Pocantico Hills mansion, which had been home to generations of Rockefellers; it was given to the National Trust for Historic Preservation and opened for public tours in 1994. But she kept a Japanese house designed by Junzo Yoshimura on the estate and an apartment in New York. She had lived in her home in Tarrytown for more than 50 years. Mrs. Rockefeller continued her husband’s activities as a patron of the arts and philanthropist, and for many years maintained a busy schedule of social, cultural and charity functions, squired by her sons and members of the Rockefeller clan.