Sen. Dianne Feinstein (D-Calif.), a vocal advocate of gun control measures who was known for trying to find common ground with Republicans during her three decades in the Senate, has died, her office confirmed on Friday.

She was 90.

“Senator Feinstein never backed away from a fight for what was just and right. At the same time, she was always willing to work with anyone, even those she disagreed with, if it meant bettering the lives of Californians or the betterment of our nation,” her chief of staff, James Sauls, said in a statement. Feinstein’s office did not share a cause of death, but she had been experiencing rapidly declining health in recent months.

“There are few women who can be called senator, chairman, mayor, wife, mom and grandmother. Senator Feinstein was a force of nature who made an incredible impact on our country and her home state.”

Feinstein, the oldest member of the Senate, the longest-serving female senator and the longest-serving senator from California, announced in February that she planned to retire at the end of 2024, when her term is up. She had faced calls for her resignation over concerns about her health.

Pennsylvania’s senators spoke on the passing of Feinstein.

My statement on the passing of Senator Feinstein: pic.twitter.com/UHm6ieCqru

— Senator Bob Casey (@SenBobCasey) September 29, 2023

Senator Feinstein was a true trailblazer in American politics who led on issues like gun violence protection and LGBTQ rights.

Gisele + I send our deepest condolences to her family, staff and loved ones in this difficult time.

— Senator John Fetterman (@SenFettermanPA) September 29, 2023