The White House on Wednesday called Frank Kameny an American hero in mourning his death.

Kameny died in his Washington D.C. home on Tuesday. Authorities believe he died in his sleep of natural causes. He was 86.

Kameny, who was fired in 1957 by the United States government because he was gay, co-founded the Mattachine Society of Washington, one of America's earliest gay rights groups.

John Berry, the director of the U.S. Office of Personnel Management, mourned the loss in a statement. Berry is openly gay.

“Dr. Frank Kameny was an American hero who transformed our nation's lesbian, gay, bisexual and transgender community (LGBT). His courage, his brilliance, his force of will led to victory in a decades-long fight for equality. He helped make it possible for countless patriotic Americans to hold security clearances and high government positions, including me. And in so doing, he showed everyone what was possible for every employer in our country,” Berry wrote.

“He was known for being feisty and combative, but he was also big-hearted. He honored me personally by attending my swearing-in, and showed his ability to forgive by accepting my official apology on behalf of the government for the sad and discredited termination of his federal employment by the U.S. Civil Service Commission, the predecessor of the agency I now head. We presented and he accepted OPM's highest honor, the Theodore Roosevelt Award, given to those who are courageous in defense of our nation's Merit Principles.”

“I am grateful for his life, his service to his nation in WWII, and his passion and persistence in helping build a more perfect union. He was a great man, and I will sorely miss him.”