Pioneering lesbian activist Phyllis Lyon has died at 95 of natural causes.

California Governor Gavin Newsom, who as mayor of San Francisco officiated her wedding to her late wife Del Martin in 2008, shared the news on Twitter.

“Phyllis and Del were the manifestation of love and devotion,” Newsom wrote. “Yet for over 50 years they were denied the right to say 2 extraordinary words: I do.”

“Phyllis – it was the honor of a lifetime to marry you and Del. Your courage changed the course of history. Rest in Peace my dear friend,” he added.

Lyon and Martin moved in together in 1953, three years after they met. Together they founded the Daughters of Bilitis (DOB), the first social and political organization for lesbians in the United States, in 1955. The group put out The Ladder, the first nationally distributed lesbian publication in the United States. Lyon and Martin became the first lesbian couple to join the National Organization for Women (NOW).

In the late 1960s and 70s, the women used their influence to decriminalize homosexuality in California.

In 2004, then-Mayor Gavin Newsom ordered San Francisco to begin marrying gay and lesbian couples. Lyon and Martin were the first to wed. But that marriage was voided by the California Supreme Court. In 2008, the California Supreme Court legalized same-sex marriage and the couple was married again in a ceremony presided by Newsom, becoming the first same-sex couple to marry in San Francisco after it was legalized statewide.

“This is an extraordinary moment in history,” Newsom said in marrying the couple. “I think today, marriage as an institution has been strengthened.”

Martin died two months after her wedding. She was 87 at the time.

California State Senator Scott Weiner, chairman of the LGBTQ caucus, said in a tweet that Lyon and Martin “played a crucial role [in] winning the rights & dignity our community now enjoys. We owe Phyllis intense gratitude & love for her work.”