The Human Rights Campaign (HRC), the nation's largest LGBT rights advocate, is mourning the loss of Georgia Representative John Lewis.

Lewis died late Friday at the age of 80 after battling pancreatic cancer.

Lewis was best known for his work in the Civil Rights Movement. He fought to secure voting rights for Black Americans and end segregation in the United States.

Lewis was also a vocal supporter of LGBT rights. In 1996, Lewis delivered a speech on the House floor against the Defense of Marriage Act (DOMA), the law that prohibited federal agencies from recognizing the legal marriages of gay and lesbian couples. It was a rare showing at the time of public support for same-sex marriage.

In a 2003 editorial, Lewis called on readers to support LGBT rights.

“I have fought too hard and too long against discrimination based on race and color not to stand up against discrimination based on sexual orientation,” he wrote in the Boston Globe. “I've heard the reasons for opposing civil marriage for same-sex couples. Cut through the distractions, and they stink of the same fear, hatred, and intolerance I have known in racism and in bigotry.”

HRC President Alphonso David said in a statement that Lewis had “pushed our country closer to the promise of a more perfect union.”

“Future generations will learn how he faced down discrimination with courage and defiance, boldly challenging the United States to envision a future where every person, no matter their race, sexual orientation or gender identity, has an equal chance at the American Dream. His legacy will live on in the work we do every day to further his mission and continue to get into ‘good trouble’ in the name of equality and justice. We join the nation in mourning the loss of this giant, and share our deepest condolences with Congressman Lewis’ family and loved ones,” David said.

HRC added that Lewis had earned a 100 rating on its Congressional Scorecard, a measure of a lawmaker's support for LGBT rights.