Activist Phyllis Lyon, who spent more than 50 years fighting for LGBTQ rights, died of natural causes. She was 95.
California Gov. Gavin Newsom shared the news of Lyon's death in a post on Twitter on Thursday, calling her a "dear friend."
When Newsom served as mayor of San Francisco, he officiated the wedding between Lyon and her late partner Del Martin in 2008.
In 2004, San Francisco officials allowed gay couples in the city to wed, prompting a flood of applicants to the City Hall clerk's office. The officials chose Lyon, then 80, and Martin, then 83, to take the first vows. Those unions were voided by California's Supreme Court, until 2008 when it struck down the state's ban on same-sex marriage. The ruling paved the way for same-sex couples to marry in the state -- and Lyon and Martin chose to get remarried.
"Phyllis—it was the honor of a lifetime to marry you & Del," Newsom wrote in the tweet, which was accompanied by a video of the two of them. "Your courage changed the course of history."
Lyon and Martin, who passed away in 2008, first met back in 1950. Together, they were pioneers in fighting for same-sex marriage in California.
The couple founded the Daughters of Bilitis -- the first lesbian rights organization in the US -- in 1955.
Both are considered champions of the LGBTQ rights movement.
Lyon died of natural causes, California State Sen. Scott Weiner, who is chairman of the LGBTQ caucus, confirmed in a tweet.
"We lost a giant today," Weiner wrote. "Phyllis Lyon fought for #LGBT equality when it was neither safe nor popular to do so. Phyllis & her wife Del played a crucial role winning the rights & dignity our community now enjoys. We owe Phyllis intense gratitude & love for her work."
Kate Kendall, former executive director of the National Center for Lesbian Rights, said she will miss Lyon.
"She and Del are dancing again," she wrote on Twitter. "I will miss her so much."