Susan Wojcicki, the former CEO of YouTube and one of the most influential female executives in Silicon Valley, died on Friday after two years of living with lung cancer, the company announced.
Last year, she stepped down from her role after more than two decades leading various parts of Google and its parent company Alphabet.
“Even as I write this it feels impossible to me that it’s true,” Alphabet CEO Sundar Pichai wrote in a note to staffers on Friday that was published on the company website.
“Her loss is devastating for all of us who know and love her, for the thousands of Googlers she led over the years, and for millions of people all over the world who looked up to her, benefited from her advocacy and leadership, and felt the impact of the incredible things she created at Google, YouTube, and beyond.”
Wojcicki was a key figure at Google from the company’s earliest days, when she rented her Palo Alto garage to founders Larry Page and Sergey Brin.
In 2016, Wojcicki spoke at Fortune’s Most Powerful Women Summit with creator Grace Helbig and Fortune’s Jennifer Reingold on the evolution of media, the creator economy, and her vision for YouTube as the future of TV.
Read Fortune’s obituary for Susan Wojcicki here.