Women’s times have improved in the decades since; Paula Radcliffe of Britain set the fastest time to date, 2:15:25, at the 2003 London Marathon.

Dale Sheldon Grieg was born on May 15, 1937, in Paisley, about 10 miles west of Glasgow. She started as a sprinter in school before extending herself to races of 880 yards and a mile, winning four bronze medals at the latter distance between 1958 and 1966 in the Scottish women’s national championships. In 1960, she won the first of four national titles in cross-country races.

By 1964 she felt ready for that first marathon on the Isle of Wight, off the southern coast of England. She was confident in her preparation, which focused on training runs of at least 30 miles. On race day, May 23, 1964, she had the stamina to catch up to some of the men in the last few miles.

The organizers’ decision to let her race — albeit by having her start before the men — earned them a reprimand from a regional athletics association that reflected the state of women’s amateur athletics at the time. In a letter, the group warned that “in athletics women are not allowed to compete with men” because “the resulting publicity is not good for the sport.”

She continued to race all the same, including in the Isle of Man 40-mile race and the Ben Nevis 10-mile mountain marathon in Scotland, both in 1971. She gave up the sport in 1982, after she cracked bones in the heels of both feet jumping into a pool; she had misjudged the depth of the water.

No immediate family members survive. Her twin sister, Cynthia, died in 2013.

Greig, who worked for many years in a printing business and as a race organizer and track writer, earned no money from her races, although she did win prizes, including cutlery sets and table lamps.

“I believe in the amateur code and actually gave away my prizes,” she told the Scottish newspaper The Herald in 2015.

Arnold Black, the historian for Scottish Athletics, the country’s governing body for track and field, wrote about Greig on the organization’s website:

“Her pioneering efforts opened the way for women throughout the world to be admitted to marathon races, having ventured into uncharted territory at a time when some respected authorities still believed that running such long distances was harmful for a woman.”