LONDON – George Martin, the Beatles’ urbane producer who quietly guided the band’s swift, historic transformation from rowdy club act to musical and cultural revolutionaries, has died, his management said Wednesday. He was 90.

Too modest to claim the title of the fifth Beatle, the tall, elegant Londoner produced some of the most popular and influential albums of modern times – “Sgt. Pepper’s Lonely Hearts Club Band,” “Revolver,” “Rubber Soul,” “Abbey Road” – elevating rock LPs to art forms: “concepts.”

Martin won six Grammys and was inducted in 1999 into the Rock and Roll Hall of Fame. Three years earlier, he was knighted by Queen Elizabeth II.

Former Beatle Paul McCartney said Martin had been “a true gentleman and like a second father to me.”

“If anyone earned the title of the fifth Beatle it was George,” McCartney said. “From the day that he gave the Beatles our first recording contract, to the last time I saw him, he was the most generous, intelligent and musical person I’ve ever had the pleasure to know.”

Beatles drummer Ringo Starr tweeted: “God bless George Martin peace and love to Judy and his family love Ringo and Barbara. George will be missed.”

Martin witnessed and enabled the metamorphosis of the Beatles and of the 1960s. From a raw first album in 1962 that took just a day to make, to the monthslong production of “Sgt. Pepper,” the Beatles advanced as songwriters and sonic explorers. They composed dozens of classics, from “She Loves You” to “Hey Jude,” and turned the studio into a wonderland of tape loops, multi-tracking, unpredictable tempos, unfathomable segues and kaleidoscopic montages.

Adam Sharp, a founder of CA Management, said in an email that Martin “passed away peacefully at home.”

McCartney said with Martin’s death, “the world has lost a truly great man who left an indelible mark on my soul and the history of British music.”

Martin is survived by his wife Judy and four children from two marriages.