Laura Pollan, 63, a high school teacher who captured international attention by leading the wives, sisters and mothers of Cuban political prisoners in weekly protest marches through the streets of Havana, died Oct. 14 at a hospital in the capital.

Hector Maseda, an independent journalist who had been imprisoned for eight years by the Castro government, told the Associated Press that his wife, Ms. Pollan, died from a cardiorespiratory attack.

Maseda was arrested in March 2003 with 74 other Cuban journalists and regime critics in a crackdown that became known as “Black Spring.” Ms. Pollan and the women she quickly mobilized called themselves the Ladies in White.

Every Sunday, they gathered at the church of Saint Rita, a patron of lost causes. Dressed in white, each with a flower in hand, they would begin their march down the street known as Fifth Avenue.

“She was astonishing,” said Ann Louise Bardach, a Cuba expert and the author of the book “Without Fidel.” “What this woman did is say, ‘We’re not going to be privately complaining in our kitchens. We’re going to take this to the streets. . . . It was very moving, and very threatening to the government.”

The protests that Ms. Pollan led were unrelenting. According to a report published in the Christian Science Monitor in 2008, the marches even continued on three occasions when tornadoes struck Havana. She and the other women endured insults and beatings from government supporters. On occasion, security forces moved the women onto buses and ordered that they be driven away.

Ms. Pollan, whose resources were limited, ran the protest operation from her Havana home. Branded as a “mercenary,” she lived the dangerous life of a dissident. The government tormented her and other wives by moving the men to prisons far from their homes. Sometimes phone privileges were granted only on Sundays, when government officials knew the women would be protesting, the Associated Press said.

But the Castro government proved unable or unwilling to completely muzzle the Ladies in White, especially after the European Parliament awarded the group the Sakharov Prize for freedom of thought in 2005. (The government did not allow Ms. Pollan to leave Cuba to accept the prize.)

Maseda had been sentenced to 20 years, other men to as many as 28 years. Some were released for medical reasons, but by last year about 50 remained in custody. In a deal that involved the Spanish government and the Catholic Church, Cuban president Raul Castro agreed to release the remaining detainees. Maseda, among the last prisoners to be freed, went home Feb. 12, 2011.

After her husband’s release, Ms. Pollan said that she would go on leading the women in their protest against a government that continued to be repressive. Several years ago, she had staked out that role for herself.

“I started fighting for my husband, then for the group, and now it’s for changes for the better of the country,” Ms. Pollan told the Monitor in 2008. “We found qualities in ourselves we did not know we had.”

Laura Pollan Toledo was born Feb. 13, 1948, in the eastern Cuban town of Manzanillo.

According to newspaper profiles, before her husband was arrested she had little to do with his political activities. Rather, she was, as she described herself, “a simple wife.” Besides Maseda, survivors include a daughter, Laura Labrada.

The day she came home and saw her husband being taken away, Ms. Pollan said, her life changed entirely.

“Those moments, what I felt, I don’t think I could ever put into words,” Ms. Pollan told the Miami Herald in 2004. “It was very painful to come home to that.”

Bardach noted the poignancy in her death: “Her husband is finally out of jail,” Bardach said, “and she’s gone.”

The Associated Press contributed to this report.