Playboy founder Hugh Hefner, the robe-clad, pipe-smoking avatar of the sexual revolution who grew his erotic publication into a multimedia empire, died at his famed Los Angeles mansion on Wednesday. He was 91.

“My father lived an exceptional and impactful life as a media and cultural pioneer and leading voice behind some of the most significant cultural movements of our time in advocating free speech, civil rights and sexual freedom,” said Cooper Hefner in a statement that added his father died of natural causes.

Born in Chicago in 1926, Hugh Hefner started on a journey that would change the very way Americans looked at sex when he borrowed $8,000 in 1953 to start publishing Playboy magazine.

At a time when states could legally ban contraceptives, when the word “pregnant” was not allowed on “I Love Lucy,” Hefner’s first issue included nude photos of Marilyn Monroe.

The magazine was no simple smut mag, however, and it gained a reputation for sophistication, with long-form journalism and fiction by the likes of John Updike, Vladimir Nabokov and Ray Bradbury.