Arnie Kantrowitz, a pioneering activist for LGBTQ+ rights and founding member of GLAAD, has died at age 81.

Kantrowitz died January 21 at a Manhattan rehabilitation center, his life partner, Dr. Lawrence D. Mass, told The New York Times. The cause of death was complications of COVID-19.

Kantrowitz was “an early champion of gay rights and an indefatigable campaigner for fairer treatment of gay people by the media,” the Times notes. Mass, a founder of Gay Men’s Health Crisis, called Kantrowitz “a true sage and champion.”

He became vice president of the Gay Activists Alliance, one of the first groups founded in the wake of the Stonewall riots, in 1970. That was also the year he came to terms with being gay, according to the Times. He helped found GLAAD, then known as the Gay and Lesbian Alliance Against Defamation, in 1985.

He was a professor in the English department at the City University of New York’s College of Staten Island from 1965 to 2006, and while there he created one of the first gay studies courses in the nation. He promoted the work of Walt Whitman and other gay writers.

In 1977 he published a memoir, Under the Rainbow: Growing Up Gay, in which he chronicled the difficulties he and other gay people faced in mid-century America. He twice tried to take his own life, he reported. He also described events in the gay rights movement, including New York City’s first Pride march. Much later, in 2009, he was grand marshal of the Staten Island Gay Pride Parade.

He was a contemporary and friend of many fellow activists, including Vito Russo, author of The Celluloid Closet. He appeared in Vito, a 2011 documentary about Russo, and several other documentaries about the LGBTQ+ community, including Gay Sex in the ’70s and After Stonewall.He also was one of the first out gay guests on popular radio and TV talk shows, speaking to Geraldo Rivera, Sally Jessy Raphael, and more.

Tributes are pouring in. “Arnie Kantrowitz’s activism paved the way for the growing visibility, protections, and acceptance of the LGBTQ community that we see today,” said a statement from Sarah Kate Ellis, president and CEO of GLAAD. “At a time when LGBTQ people were villainized in the public sphere, Arnie bravely used his personal story to educate the public about our community and its history, ultimately fighting for the fair and accurate representation of LGBTQ people and our issues in the media. His legacy inspires us to continue fighting for a future where the most marginalized among us are seen, heard, and protected.”

“He was thoughtful, charming, and like any good professor (he was among the first to teach a course in gay literature, in 1973), a lifelong student and teacher,” former White House staffer Jeremy L. Léon, who interviewed Kantrowitz for a book, wrote on Facebook. He noted that after the formal interview was over, “we spent another six hours talking into the night like old friends.”

“So much of LGBTQ history has been documented, explored, shared, & preserved because of the actions of a handful of people, and he was one of them,” LGBTQ+ media scholar Lauren Herold wrote on Twitter. Also on Twitter, journalist Jay Blotcher commented, “The #LGBTQ community owes this man a great deal for our current #liberation.”