One by one, the paintings were snatched from the walls at gunpoint. Only the most valuable were taken. A Vermeer. A Goya. A Velázquez and others.

When the gang of Irish Republican Army raiders sped off into the night in April 1974 from an estate south of Dublin, 19 masterpieces were crammed into the car. Sitting amid the haul was the architect of the theft: Rose Dugdale, an Oxford-educated heiress who had once curtsied before Queen Elizabeth II during a debutante soiree at Buckingham Palace.

Ms. Dugdale, who had left behind her previous life, saw the looted art as bargaining chips to free IRA prisoners. Instead, the paintings were recovered and she was jailed – capping her evolution as she embraced the IRA’s battle against British rule of Northern Ireland, including once leading an audacious attempt to bomb a police station from a hijacked helicopter.

Ms. Dugdale, who died March 18 at a nursing facility in Dublin at the age of 82, also relished casting scorn on the upper-crust English background she rejected. Time magazine dubbed her the “Renegade Debutante” – she carried out the art robbery just weeks after newspaper heiress Patty Hearst had been seen robbing a bank in San Francisco with a self-styled revolutionary group called the Symbionese Liberation Army.

“I love you,” Ms. Dugdale said to her father during one of her court hearings in the 1970s, “but I hate everything you stand for.”

The decades of sectarian bloodshed over Northern Ireland, known as the Troubles, had many backstories before peace accords were reached in 1998 to mostly end the fighting that claimed more than 3,500 lives. The IRA once found support among the Irish diaspora, and even from regimes such as Libya, Britain claimed. One day in late 1973, the improbable militant, Ms. Dugdale, entered the picture.

She made contact with IRA commanders, offering to help buy some weapons in exchange for being welcomed into their fold, court records and biographies said. Ms. Dugdale was not unknown to the IRA. She had already made headlines for rebelling against her pedigree.

Ms. Dugdale was raised with all the advantages of her moneyed lineage – a father who ran a lucrative insurance underwriting syndicate at Lloyd’s, and a mother from a wealthy old-money family. As a teenager, Ms. Dugdale went on a classic European Grand Tour and then was part of the 1958 debutante ceremony hosted by the queen, where the young women entering high society nibbled on chocolate cake and hobnobbed with royalty.

Ms. Dugdale didn’t want to attend, she recalled, but was cajoled by appeals from her mother. Later, at St. Anne’s College, part of the University of Oxford, Ms. Dugdale showed further sparks of dissent. She dressed as a man and gate-crashed the Oxford Union debating society to protest its male-only membership.

Ms. Dugdale went on to receive a doctorate in economics and began a career in academia. Her views, however, were being shaped by other forces, such as the antiwar protests and civil rights movements of the 1960s.

She became interested in communism after a trip to Cuba. By the early 1970s, she had resigned from her teaching post, sold her house in London’s posh Chelsea neighborhood and cashed in her share of the family holdings in Lloyd’s. She used the small fortune for projects such as distributing food and aid to low-income families. She joined marches against apartheid and traveled to conflict-battered Northern Ireland with her then-partner, Walter Heaton, a former British army soldier who described himself as a “radical socialist.”

In June 1973, Ms. Dugdale and Heaton were arrested after a break-in at the 600-acre Dugdale family estate in Devon, the same grounds where she rode her pony Eros as a girl. Ms. Dugdale and Heaton were charged with stealing paintings, silverware and antiques valued at more than $150,000. Police claimed Heaton, who had IRA connections, had planned on funneling some of the money to the group.

Heaton was convicted and sentenced to six years in prison. Ms. Dugdale received a two-year suspended sentence, with the judge declaring that she was unlikely to commit criminal acts in the future. She openly mocked the ruling. “In finding me guilty you have turned me from an intellectual recalcitrant into a freedom fighter,” she told the court. “I know no finer title.”

Within months, she was establishing footholds with the IRA. “No, I cannot say I do regret it,” Ms. Dugdale was quoted as saying in Sean O’Driscoll’s biography “Heiress, Rebel, Vigilante, Bomber: The Extraordinary Life of Rose Dugdale” (2022). “There was no way, after a certain point, that I would turn back.”

In Ireland’s County Donegal in January 1974, she posed as a freelance photojournalist to hire a helicopter. Once the chopper was airborne, Ms. Dugdale and IRA foot soldier Eddie Gallagher demanded that the pilot land. They loaded aboard large milk jugs, known as churns, packed with explosives. The pilot was then forced to fly over the Northern Ireland border to Strabane, where Ms. Dugdale and Gallagher dropped the improvised bombs on a police station.

The charge failed to detonate, and the devices landed without causing injury. Ms. Dugdale called it “the happiest day of my life” for trying to bring chaos. “It was the first time I felt at the center of things,” she told O’Driscoll, “that I was really doing as I said I would do.”

Less than four months later, Ms. Dugdale showed up at the door of Russborough House, the country mansion of Alfred Beit, a former British member of Parliament and heir to a South African mining fortune. Ms. Dugdale pretended to be a French tourist whose car broke down.

Suddenly, her IRA comrades burst in. Beit was roughed up. Ms. Dugdale stood guard over Beit and his wife, shouting at the couple, “Capitalist pigs!,” she recalled. The IRA gunmen roused a 17-year-old maid out of the bath to direct them to the rooms with the valuable artworks. Among the works stolen were Francisco Goya’s “Portrait of Doña Antonia Zárate”; Diego Velázquez’s “Kitchen Maid with the Supper at Emmaus”; and Johannes Vermeer’s “Lady Writing a Letter with her Maid.”

“They deserved it, every bit of it,” Ms. Dugdale later said.

She and the gunmen drove to County Cork, where she booked a cottage under the name Mrs. Merrimée. A note sent to the National Gallery of Ireland demanded the release of four IRA prisoners from British custody.

Police visited the cottage during the nationwide hunt for the paintings. Ms. Dugdale stayed in the guise of a lone French tourist, she said. Police were not fooled. A raid turned up three of the stolen paintings in the cottage. The others were found stacked in the trunk of a car.

By this time, Ms. Dugdale had fled and was eventually caught in the Cork village of Baltimore, the name of a film on Ms. Dugdale’s life that is scheduled for release this week. (The Beit collection also was hit repeatedly by other art thieves in decades afterward.)

Ms. Dugdale pleaded “proudly and incorruptibly guilty,” and was sentenced to nine years in prison for her part in the robbery and the attack on the police station in Strabane.

After being jailed, Ms. Dugdale discovered she was pregnant and said the father was Gallagher, who was a fugitive. A year later, Gallagher kidnapped the Dutch industrialist Tiede Herrema in Limerick to demand Ms. Dugdale’s release. A more than two-week siege at his hideout ended with Gallagher surrendering. Herrema was unharmed.

“You mustn’t forget it was very exciting times … the world looked as if it could change and was likely to be changed,” Ms. Dugdale told Irish state broadcaster RTÉ in 2014, “and, whoever you were, you could play a part in that.”

Nicknamed Rose

Bridget Dugdale was born March 25, 1941, on the family’s Devon estate in southwestern England. At the time, her father was serving with the British military in North Africa. When her father returned home, he nicknamed her Rose.

She graduated from St. Anne’s College in 1962, and then received a master’s degree in philosophy at Mount Holyoke College in South Hadley, Mass. Her application included a letter of recommendation from novelist Iris Murdoch, one of Ms. Dugdale’s professors at Oxford.

Ms. Dugdale returned to London in 1965 to work as a government economic adviser specializing in developing countries. After receiving her doctorate in economics at Bedford College in London (now part of Royal Holloway College), she remained on campus as a lecturer.

In 1978, she and Gallagher were permitted to marry while in prison. She was released in 1980 and was reunited with her son, Ruairí. She later began a relationship with Jim Monaghan, an IRA bomb maker.

In O’Driscoll’s biography, Ms. Dugdale claimed she had a role in helping develop IRA bombs used in major attacks in early 1990s, but no charges were filed.

Ms. Dugdale and Gallagher were estranged, but they remained married. Survivors include their son. Irish media reported the death, but no cause was noted.

Ms. Dugdale spent the rest of her life in Dublin after leaving prison. She worked with various charities and was an active member of Sinn Féin, founded as the political wing of the IRA.

Her death also leaves open one mystery: Who stole a Vermeer painting, “The Guitar Player” from a museum in Hampstead, England, in February 1974? A ransom note asked for the release of two sisters imprisoned for IRA ties. No one was charged with the theft, but authorities said Ms. Dugdale was a chief suspect.

The painting was found in a London cemetery two days after her arrest for the Beit heist. A Scotland Yard statement said the Vermeer “was propped up against a gravestone, wrapped in newspaper and tied with a string.”

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