Windsor was the lead plaintiff in the Supreme Court case United States v. Windsor, which successfully struck down the Defense of Marriage Act (DOMA) in 2013 and gave same-sex couples federal recognition and benefits for the first time.
Born in 1929, Windsor - her married name from a brief heterosexual marriage - held a master's degree in applied mathematics from New York University and worked as a computer programmer at IBM from 1958-1975.
Michelle and I offer our condolences to her wife, Judith, and to all who loved and looked up to Edie Windsor.
"I lost my beloved spouse Edie, and the world lost a tiny but tough as nails fighter for freedom, justice and equality", Kasen-Windsor, who married Edith in 2016, said in a statement, according to Colin Dwyer of NPR. "What a life. Thank you, Edie".
After her win, she attended services at her Manhattan synagogue, Beit Simchat Torah, which was founded to serve the gay community, and listened to her lawyer, Roberta Kaplan, deliver a sermon on the win. That meant Windsor faced a $360,000 tax bill that heterosexual couples would not have. In 2007, they legally married in Canada - a union that was recognized by the state of NY. After the 1969 Stonewall Riots, they started marching in pride parades and joined LGBTQ organizations.
Windsor once told NPR "marriage is this magic thing" in the battle for homosexual rights.
Spyer was diagnosed with multiple sclerosis in 1977, and her physical condition deteriorated over the decades. By 2007, her prognosis was looking grim. The women married in Canada when they realized they might not live long enough to see NY legalize same-sex marriage.
Steve Silberman, a journalist and the author of a Neurotribes, a book about neurodiversity, said Windsor changed the course of his life.
Days after the rally, Spyer died.
In 2009, Windsor was denied a spouse's exemption and forced to pay federal taxes on the estate of her late wife, Thea Spyer, who also was Jewish, although their Canadian marriage was recognized as legal by the State of NY, where they resided.
Edie Windsor, whose fight for marriage equality ended with a historic victory and was suffused with her Jewish sensibility, has died at 88. And in 2013, the Supreme Court agreed, overturning DOMA in a landmark victory for LGBT rights.
Outraged, she went to court, knowing that the case was about more than taxes or even marriage.
The case also turned Windsor into an LGBTQ icon.
Former President Barack Obama called her one of the "quiet heroes" whose persistence had furthered the cause of equality. Windsor said that she hoped that time in 2013 would be remembered as "the time when everybody [who had] an out-of-country partner [could] bring them home to America". She also served as the grand marshal of New York City's Pride March.
"Our choice not to wear traditional engagement rings was just one of many ways in which Thea and I had to mold our lives to make our relationship invisible", Windsor said in court documents. "I got a million letters". It's bigger than marriage, and I think marriage is major.