Ms. Nixon was a dominant force in daytime TV. The National Academy of Television Arts and Sciences called her "the grand dame of daytime serial drama" when she won a Daytime Emmy Award for lifetime achievement in 2010.

Ms. Nixon's work broke barriers by addressing topics such as abortion, AIDS, and same-sex marriage before prime-time outlets touched on those controversies. "Agnes was responsible for so many bold stories. They were social motivators and Agnes was at the forefront of that," said Jessica Klein, the head writer of the revived online version of One Life to Live and former Drexel University adjunct professor. "She was a champion of women. She never talked down to her audience. She believed in character drama, which is really what soap operas are. ... There's no harder job than writing for soap operas. It's 52 weeks a year, and there are no repeats. Agnes never stopped."

In 2010, Ms. Nixon named Erica Kane as one of her favorites of more than 150 major characters she created. "She does outrageous things, but the audience knows that as much havoc as she causes in the lives of others, she torments herself even more," Ms. Nixon said of Lucci's character.

Ms. Nixon was born in Chicago and began writing for soaps under her mentor,  Irna Phillips, creator of soap operas such as Guiding Light and its sister show, As the World Turns. As the head writer for Guiding Light, she started tackling difficult topics. In 1962, after losing a friend to cervical cancer, she wrote a storyline about uterine cancer without using the words uterus, cancer, or hysterectomy.

In 1951, she married Robert H.A. Nixon. He died in 1996.

"She would go to New York every other weekend for meetings and she'd bring me Jordan almonds, candy from the train," she said.

"The thing as an adult that I look back on is, she really made people look at stigma and people's own feelings about a lot of important issues in her time and in our time," Mary said. "She really wanted to help people learn and grow. It was more than just about how many marriages. … [It was to help viewers] have a better understanding of life."

A visitation will be from 6 to 9 p.m. Friday, Sept. 30, at McConaghy Funeral Home, 328 Lancaster Ave., Ardmore. A Funeral Mass will be at 10:30 a.m. Saturday, Oct. 1, at St. Thomas of Villanova Rosemont Chapel, 1229 E. Lancaster Ave., Rosemont.

Donations may be made to National Parkinson Foundation, 200 S.E. First St., Suite 800, Miami, Fla. 33131 or Wilmer Eye Institute, 600 N. Wolfe St., Baltimore, Md. 21287.

*An earlier version of this story incorrectly put Ms. Nixon's age at 88. She was 93.