Story highlights Edith Windsor won the Supreme Court case that overturned DOMA

She had sued over a tax bill and it led to equality for same-sex married couples

(CNN) Edith Windsor, the plaintiff in the 2013 United States Supreme Court case that struck down the Defense of Marriage Act -- which had defined marriage as between a man and a woman -- died Tuesday. In an op-ed for CNN later that year, she reflected on her decision to seek justice.

On Sunday, I will have the honor of serving as grand marshal in the New York City Pride Parade. I have marched in the parade for the last several years carrying a huge rainbow flag. Last year, I was so elated that I danced my way down the street for the entire route.

Before that, my late wife Thea and I, she in her wheelchair, would watch the parade together every year. If someone had told me 50 years ago that I would be the marshal of the New York City Gay Pride Parade in 2013 at the age of 84, I never would have believed it.

Over the past couple of years, many people have asked me, "Why did you decide to sue the United States over a tax bill?" Because the answer is complex, let me give you some of the background.

I lived with and loved my late spouse, Thea Spyer, for more than four decades in love and joy, and in sickness and health, until death did us part. When Thea died in 2009 from a heart condition two years after we were finally married, I was heartbroken.

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