(CBS) — John McCain, the military hero who had a long career as a “maverick” Republican senator, has died, his Senate office confirmed on Saturday. He was 81.

In a statement, his Senate office said he died at 4:28 p.m. on August 25, surrounded by his wife Cindy and his family.

McCain was diagnosed with glioblastoma, an aggressive form of brain cancer, in July 2017.

On August 24, McCain’s family said that “with his usual strength of will,” he had chosen to discontinue treatment.

Though McCain had “surpassed expectations for his survival, … the progress of disease and the inexorable advance of age render their verdict,” the statement said.

Friends and colleagues expressed their thoughts and condolences on social media following the news of McCain’s death.