WASHINGTON — A hundred years after the execution of Mata Hari, the Dutch double agent who was one of the most famous spies of the 20th century, historians are debunking many of the myths about her that have endured for decades.

Mata Hari has long been revered as the ultimate femme fatale — the seductive, glamorous, exotic dancer who spied for the Germans during World War I and caused the deaths of thousands of Allied soldiers.

She has captured the imaginations of people around the world long after she met her fate. This influence on popular culture was fueled by Greta Garbo’s portrayal of her in the 1931 film, ‘‘Mata Hari,’’ which was repeatedly censored for its risqué scenes.

But earlier this year, trial archives kept confidential by the French were released to the public. And a cache of Mata Hari’s personal and family letters was recently published.

Taken together, the documents recast the Great War’s most notorious spy as a mother who left an abusive marriage and as a scapegoat for war-torn France looking to distract from heavy casualties on the front lines.

‘‘We wanted to try to get a grip of her life, not only as a big star but also as a mother, as a child, as someone who is not only the dancer or the beauty queen, but the complete picture,’’ said Hans Groeneweg.

Groeneweg is the curator of a museum exhibit on Mata Hari, which opened Saturday at the Museum of Friesland in her hometown of Leeuwarden in the Netherlands.

In the early hours of Oct. 15, 1917, Mata Hari was shaken awake in her prison cell. Her time had come.

Given a pen, ink, paper, and envelopes, she was allowed to write two letters, according to an account by journalist Henry G. Wales, a correspondent for the International News Service. She hastily scribbled the notes before donning her black stockings, high heels, and a velvet cloak lined at the bottom with fur.

‘‘I am ready,’’ the 41-year-old spy said.

She was driven from her cell in the Saint-Lazare prison to an old fort on the outskirts of Paris. It was just past 5:30 a.m. when she faced her firing squad: 12 French officers with their rifles at ease.

Offered a white cloth to wear as a blindfold, Mata Hari refused, saying: ‘‘Must I wear that?’’

She then stared steadfastly as the soldiers fired.

Mata Hari was born Margaretha Geertruida Zelle to a prosperous family in 1876. When Margaretha was a teenager, her father, a hat seller, lost his fortune and left the family. Then her mother died when Margaretha was 15, and she was sent away to live with relatives.

At 18, Margaretha met and soon married Rudolph John MacLeod, an officer in the East Indies Army who was almost twice her age. The couple left for the Dutch East Indies, where they lived for four years in military garrisons.

But the marriage was troubled at best and abusive at worst. In one of her letters, Margaretha wrote that Mac-Leod ‘‘came close to murdering me with the bread knife. I owe my life to a chair that fell over and which gave me time to find the door and get help.’’

The couple also lost a son and nearly lost a daughter after both were widely rumored to have been poisoned by a nanny, though it’s unclear whether the story is true.

The couple eventually returned to Holland and separated, but MacLeod refused to pay alimony to help her raise their daughter.

She ultimately went to Paris and left her daughter with her ex-husband.

‘‘She had to make a choice: go to France and get a life for herself, or be poor and live in poverty and try to raise her child,’’ Groeneweg said. ‘‘She chose to go to France and build up a career, but she always missed her girl.’’

In another letter, she wrote that she had secured a job with a theater company but was also sleeping with men for pay.

‘‘Don’t think that I’m bad at heart,’’ she wrote to her ex-husband’s cousin, who had been acting as an intermediary. ‘‘I have done it only out of poverty.’’

It was in her acting and dancing roles that Margaretha took on the name that would outlive her: Mata Hari.

Perhaps the most significant plot twist to Mata Hari’s legacy is that she did not divulge any information of consequence to the Germans.

Shamed in the international press as a traitor, she was accused of revealing closely kept secrets about Allied tanks, leading to the deaths of thousands of soldiers. Her relationships with German and French officers put her under special scrutiny, as did her travels crisscrossing through Europe during the war.

Groeneweg said Mata Hari was a ‘‘big catch’’ for the French, who were eager to jail anyone suspected of spying. Even so, Groeneweg said the French feared what Mata Hari could reveal about her dalliances with their own officers, including a high-ranking general.