In 1991, Runner’s World magazine named Waitz the female runner of the quarter-century, and she was perhaps the pre-eminent female distance runner in history. She twice set the world record at 3,000 meters, and she set world records at distances of 8 kilometers, 10 kilometers, 15 kilometers and 10 miles.

But it was in the marathon, the 26.2-mile symbol of human endurance, that Waitz most distinguished herself, setting a world record of 2 hours 32 minutes 30 seconds the first time she ran one, in New York in 1978, and subsequently lowering the world standard three more times. In addition to her New York City victories, Waitz won the London Marathon twice, the Stockholm Marathon once and the world championship marathon in 1983.

“She is our sport’s towering legend,” said Mary Wittenberg, the president of the New York Road Runners. “I believe not only in New York, but around the world, marathoning is what it is today because of Grete. She was the first big time female track runner to step up to the marathon and change the whole sport.”

Grete Waitz (whose name was pronounced GREH-tuh VITES) was not simply a champion, however; she was also something of a pioneer. At the time of her first New York victory, women’s distance running was a novelty. Just 938 out of 8,937 entrants in the 1978 New York marathon were women — in 2010, 16,253 of 45,350 entrants were — and the women’s marathon would not be added to the Olympics until the 1984 Summer Games in Los Angeles, where Waitz finished second to Joan Benoit Samuelson.

“I lost a mentor and a role model,” Samuelson, 53, said Tuesday, a day after running the Boston Marathon in 2:51:29. She decided to run at the last minute, Samuelson said, because, although she had been battling back problems, she was inspired by Waitz’s courage.

“What will endure forever is that she was able to balance a competitive career with the most gracious lifestyle, and a character that emanated good will,” Samuelson said.

Remarkably, Waitz, a champion track runner, ran her first marathon as a lark, with the encouragement of her husband, who was also her coach, and who told her that a trip to New York would be like a second honeymoon for them. Even in training she had never run more than 13 miles, and the science of the sport was young enough that her dinner the night before the race included shrimp cocktail and filet mignon, hardly the load of carbohydrates that even today’s rankest amateurs know to consume. As she recalled in later interviews, the last 10 miles of the race were agony, and she was so angry at her husband that when she crossed the finish line, she tore off her shoes and flung them at him.

“I’ll never do this stupid thing again,” she yelled.

She was, however, hooked. The next year, she finished the race in 2:27:33, beating her record by almost five minutes and becoming the first woman to officially run a marathon faster than two and a half hours. Her legendary status was assured.

In her home country, her New York victories conferred on her the status of a national hero; a statue of her stands outside Bislett Stadium, an international sports arena in Oslo, and her likeness appeared on a Norwegian postage stamp. She established a 5-kilometer race in Oslo that eventually expanded to 40,000 runners, and in 2007, she started her foundation, which sponsors runners in major races and supports cancer hospitals and patient centers.