Gay rights activist Edith Windsor, whose same-sex marriage fight led to a landmark US ruling, has died aged 88.
Her death was confirmed to the New York Times by her wife Judith Kasen-Windsor.
Ms Windsor’s Supreme Court case struck down the Defense of Marriage Act in 2013, granting same-sex married couples federal recognition for the first time.
She had sued the US government after being ordered to pay $363,053 (£224,940) in federal estate tax after her previous wife died.
The couple had been partners for 44 years and had married in Canada in 2007.
Ms Windsor argued that the provision of the law which defined marriage as between a man and a woman prevented her from getting a tax deduction due to married couples – and was unconstitutional.
In a landmark 2013 ruling the US Supreme agreed – and that decision became the basis for a wave of further court rulings increasing the rights of same-sex couples.
In 2015 another crucial Supreme Court ruling gave same-sex couples the right to marry.
Ms Windsor died in New York. A cause of death was not given, but Ms Windsor had struggled with heart issues for years, the Associated Press news agency reported.
“The world lost a tiny but tough-as-nails fighter for freedom, justice and equality,” Judith Kasen-Windsor was quoted as saying.
Former US presidents Bill Clinton and Barack Obama also paid tribute to Ms Windsor.
Mr Obama said in a statement: “America’s long journey towards equality has been guided by countless small acts of persistence and fuelled by the stubborn willingness of quiet heroes to speak out for what’s right.
“Few were as small in stature as Edie Windsor – and few made as big a difference to America.”
Bill Clinton tweeted that “in standing up for herself, Edie also stood up for millions of Americans and their rights”.