A friend, Bob Brown, confirmed her death but did not cite a cause.

Vincenz devoted more than half a century to the cause of gay equality, beginning with her first courageous pickets in Washington in the 1960s and continuing into her later years, when she acted as a keeper of the history that she and other activists had lived.

She knew firsthand the slights, injustices and humiliations facing gay and lesbian people. In 1963, while serving in the Women’s Army Corps, she was outed by a roommate and discharged.

The incident spurred her to activism. “Sometime you are the only person who can do something at a certain time,” she told an interviewer. “It’s the old question, ‘If not I, who?'”

In 1963, Vincenz joined the Mattachine Society of Washington, a gay rights organization co-founded by Frank Kameny, a Harvard-trained astronomer who had been fired from the Army Map Service because of his sexuality.

In 1965, at a time when living openly as a lesbian meant risking discrimination and ostracism, Vincenz marched in what the Library of Congress describes as the first organized picket for gay rights outside the White House. She was the only lesbian among 10 demonstrators.

“She was certainly a pioneer in that way,” Lillian Faderman, the author of the book “The Gay Revolution: The Story of the Struggle,” said in an interview. “They couldn’t get another lesbian to show her face.”

Vincenz became “the first out lesbian ever to appear on a magazine cover that was displayed on newsstands around the country,” according to Faderman, when her radiant smile was showcased on a 1966 cover of the Ladder, a periodical published by the lesbian organization the Daughters of Bilitis.

Three years later, Vincenz co-founded the gay newspaper that became the Washington Blade. And throughout the 1970s, she hosted regular gatherings at her home in Arlington, Va., making it a locus of lesbian life. One regular attendee composed a song:

“Come all you women in the D.C. vicinity

If loving women is your proclivity

Rev up your engine, roll up your bike

And point your wheels to Columbia Pike

Carlyn Springs to 8th Place; turn to the right

For Lilli’s open house on Wednesday night.”

Vincenz later became a psychotherapist, with a particular focus in her practice on empowering gay and lesbian people through counseling.

In 2013, the Library of Congress acquired Vincenz’s papers in what to her admirers was a long-awaited recognition of her importance in the gay rights movement.

The collection included, among other artifacts, two 16mm films that she had recorded at early gay rights protests. The first, from 1968, documents one of the “annual reminders” convened in Philadelphia every Independence Day from 1965 to 1969.

Vincenz titled her documentary “The Second Largest Minority” and, in seven minutes of film, recorded demonstrators dressed in business suits and dresses – their attire purposefully coordinated to make the group appear unthreatening – marching in an orderly circle.

The second film, “Gay and Proud,” runs 12 minutes and documents the first gay pride march in New York City, the Christopher Street Liberation Day March of 1970. Galvanized by the Stonewall uprising the previous year, the protesters in New York adopted a markedly more defiant tone.

“The operative word now is ‘pride,'” Mike Mashon, head of the moving image department at the library, wrote in an analysis of the two films, both of which can be viewed on the library’s website.

“It’s one thing to read about how the gay rights movement was catalyzed by the Stonewall Inn riots of June 1969, but quite another to see that tonal shift illustrated so vividly in these bookend films,” Mashon continued. “Powerful movements can begin and be sustained in unlikely places, and how fortunate we are that Lilli Vincenz was there to record this one.”

Lilli Marie Vincenz, one of two daughters, was born in Hamburg on Sept. 26, 1937. After her father’s death when she was 2, her mother married an American, and the family immigrated to the United States in 1949.

Reflecting on her early life, Vincenz told an interviewer that it “became painful after a while to realize that I was gay and I didn’t know anyone else who was gay. I was extremely lonely.”

With an affinity for literature, Vincenz received a bachelor’s degree in French and German from Douglass College, part of Rutgers University in New Jersey, in 1959. She received a master’s degree in English and comparative literature from Columbia University the following year.

During that period in her life, she began exploring her sexuality and visited a lesbian bar in Provincetown, Mass.

“At first I thought of all the consequences that could follow me from my being seen there,” she wrote in her journal. “But then I thought of all I’d gone through in these past years, and I knew I had to go – no matter what the consequences – for the sake of the past, of the pain, but also for the wishes I’d had, time and time again proclaimed to be willing, if only I had the chance. Now, I can fulfill everything. Well, that’s saying too much – I can fulfill something.”

She worked briefly as an editor at the Prentice Hall publishing house before joining the Women’s Army Corps in 1962. She was working at Walter Reed, the military hospital near Washington, when she was discharged the following year.

Vincenz was one of the first lesbian members of the Mattachine Society of Washington. She joined its executive board and was the editor of its publication the Homosexual Citizen. In addition to the picket at the White House, the group mounted demonstrations outside the Pentagon, the State Department and the U.S. Civil Service Commission.

“It was so important that we become visible,” Vincenz said, “because we weren’t really visible before.”

As she moved toward her career as therapist, Vincenz received a master’s degree in psychology from George Mason University in 1976. She received a Ph.D. in human development education from the University of Maryland in 1990.

Of her gay clients, she observed that “many of their wounds have been sustained in the pursuit of and validation of who they are and of not wanting to hide their identity or settle for less. I am grateful to be able to help and to witness their empowerment and healing.”

Vincenz’s partner of 32 years, Nancy Ruth Davis, died in 2019. She had no immediate survivors.

“What did I want to accomplish?” Vincenz told the publication Gay Today, reflecting on her life’s work. “Be with gay people, help the movement, help unmask the lies being told about us, correct the notion of homosexuality as a sickness and present it as it is, a beautiful way to love.”