Bee Gees manager Robert Stigwood has died at the age of 81. , who also produced the 1970s blockbusters Grease and “Saturday Night Fever,” has died. He was 81.

Stigwood’s office said the producer of the 1970s Grease and Saturday Night Fever died Monday, as reported by the BBC. The cause of death was not disclosed.

RIP Robert Stigwood: The former Bee Gees manager & "Grease" producer has died at age 81 https://t.co/bQOZvLBNE6 pic.twitter.com/nO6Mz9Mjma

— billboard (@billboard) January 5, 2016

The Bee Gees manager was born in Adelaide, Australia, in 1934, and moved to Britain in the 1950s, where he quickly became an important figure in the growing rock music industry.

He managed Cream and its guitarist Eric Clapton in the 1960s before becoming the manager of brothers Barry, Maurice and Robin Gibb, collectively known as the Bee Gees.

Later, Stigwood moved from music into theater and ultimately film. He is known for bringing the Broadway hit, Hair, to the London stage. He brought to film other classic theater productions including Andrew Lloyd Webber-Tim Rice musical Jesus Christ Superstar and The Who’s rock opera Tommy.

He went on to produce Saturday Night Fever. The soundtrack, which featured the Bee Gees, made superstars out of the brothers Gibb. That was followed by the 1979 release of Grease, released in 1978, which, combined with Saturday Night Fever, made John Travolta into one of the decade’s biggest stars.

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Stigwood also produced Sgt. Pepper’s Lonely Hearts Club Band, a 1978 Beatles-based movie musical which did not fare as well as his other musical endeavors.

While sequels to Saturday Night Fever and Grease were flops, Stigwood’s movie musical Evita starring Madonna as Argentine first lady Eva Peron was a hit.

Travolta paid tribute to Stigwood, saying he “changed the world and only for the better and he was certainly important to my career. His legacy lives on and he will forever be remembered.”

Spencer Gibb, who is the son of the late Robin Gibb and Stigwood’s godson, described him as “a creative genius with a very quick and dry wit.”

“I would like to thank Robert for his kindness to me over the years as well as his mentorship to my family,” Gibb wrote on Facebook. “‘Stiggy,’ you will be missed.”

Farewell beloved Robert, the great showman who taught me so much. With love, ALW.

— Andrew Lloyd Webber (@OfficialALW) January 4, 2016

Lloyd Webber also remembered Stigwood on Twitter, calling him a “great showman who taught me so much.”