Oracle Corp.’s longtime chief security officer, Mary Ann Davidson, is leaving the company as part of a recent reorganisation, according to a person familiar with the matter.

Davidson, widely regarded as one of the most senior women in the cybersecurity industry, joined Oracle in 1988 after serving as a civil engineer in the U.S. Navy.

Her nearly 40-year tenure made her a fixture in the security community and a prominent voice advocating for stronger safeguards across Oracle’s product portfolio.

The news of her departure has surprised many in the industry, given her close ties to Oracle co-founder Larry Ellison and her role as his top adviser on security.

Davidson was instrumental in supporting Ellison’s early-2000s campaign branding Oracle software as “unbreakable,” a marketing push she later described as a major challenge to uphold.

“‘Unbreakable’ gives us something to live up to,” she said in an interview. “It really does concentrate the mind wonderfully. The general thought is don’t embarrass the company. Nobody wants to be the group that makes us violate it.”

Davidson’s career path was profiled by Businessweek in 2003, which detailed her move from a product marketing role into Oracle’s secure systems division in 1993, and eventually into the role of the company’s first chief security officer.

Outside of her corporate responsibilities, she was known as an avid surfer and skier, often working remotely from Ketchum, Idaho.

Oracle declined to comment on her exit. Davidson did not immediately respond to a request for comment.