Gay rights activist Edith Windsor died in New York on Tuesday, her lawyer Roberta Kaplan said. Although the cause of death was not specified, the 88-year-old had suffered from heart ailments for years.

Windsor was an LGBT rights pioneer. It was her case from 2009 in the United States Supreme Court that helped repeal parts of a federal law against gay marriage and paved the way for marriage equality in the country. In 2015, the Supreme Court’s ruling in the case gave same-sex couples the right to marry across the US.

“Few were as small in stature as Edie Windsor – and few made as big a difference to America,” former President Barack Obama said in a statement, calling her one of the “quiet heroes” whose efforts fueled the cause of equality.

Former US Secretary of State Hillary Clinton said Windsor “showed the world that love can be a powerful force for change”.