A mere 15 runners inspired thousands when they first conquered the 24.5 mile Boston Marathon on Patriot’s Day in 1897.

For nearly 70 years, the Boston Marathon was held on Patriot’s Day, April 19, which was recognized only in Massachusetts and Maine and commemorated the start of the Revolutionary War. In 1969, the holiday was moved to the third Monday in April and since then, the race followed suit.

On April 19, 1897, after experiencing the energy of the first modern Olympic Games in Athens, Greece, Boston Athletic Association (B.A.A.) member and U.S. Olympic Team Manager John Graham conducted the first Boston Marathon. From Metcalf’s Mill in Ashland to the Irvington Oval in Boston, 10 runners ran the full 24.5 mile race and crossed the finish line. John J. McDermott of New York secured the first winning title, according to the B.A.A. website.

Samantha Moore / Art Director

Samantha Moore / Art Director

In 1924, in order to align with Olympic standards, the marathon course was extended to 26.2 miles and the starting line moved to Hopkinton.

The Boston Marathon did not permit women to run until the fall of 1971. However, this rule didn’t stop Roberta Gibb, who hid in bushes near the starting line for three years and became the first woman to run the full Boston Marathon in 1966.

In 1967, Kathrine Switzer registered as a male under the name “K.V. Switzer,” and was given a bib number. After she was identified as a woman, officials attempted to physically remove her from the race, but she persisted and finished anyway. When women were finally allowed to run in 1972, eight women registered, eight started and all eight crossed the finish line.

In 1975, the Boston Marathon became the first to include a wheelchair division and officially recognized Bob Hall as the first participant. He was promised an official B.A.A. Finisher’s certificate only if he was able to finish the race in less than three hours. He claimed his certificate after achieving a time just two minutes shy of the time limit and popularized the race for other American wheelchair competitors to come.

Former Keene resident and Industrial Engineering professor at Keene Normal School, now Keene State College, Clarence DeMar won his first of seven Boston Marathon titles in 1911. Nobody has ever broken his record of Boston wins, according to the DeMar Marathon website. Beginning in 1978, the Clarence DeMar Marathon was established in Keene to honor him and his passion for running and still does to this day.

Just four years ago, on an unforgettable day in 2013 for many New Englanders, two bombs went off at the finish line at 2:49 p.m.. A day meant for celebrations and accomplishments turned to that of destruction and terror when three people died, 260 were injured and 16 lost limbs. Each year since, many participants run the Boston Marathon to honor and remember those affected in 2013.

Geoffrey Mutai of Kenya grasped the record for the fastest marathon time ever when he ran the Boston Marathon in 2011. Bezunesh Deba of Ethiopia holds the women’s course record after she ran in 2014.

According to the B.A.A. website, participants must qualify for the event by meeting time requirements corresponding to age and gender. This year, the 121st Boston Marathon will be held on Monday, April 17 with heats beginning at 8:50 a.m..

Jessica Ricard can be contacted at jricard@kscequinox.com