Sumner Redstone, the billionaire media magnate whose family company controls CBS and Viacom, and whose career spilled over from boardrooms to gossip sheets, has died. He was 97.

Redstone’s health had been declining before his passing Tuesday, according to the Hollywood Reporter.

President and CEO of ViacomCBS Bob Bakish hailed the mogul as “a brilliant visionary, operator and dealmaker, who single-handedly transformed a family-owned drive-in theater company into a global media portfolio.”

He was a force of nature and fierce competitor, who leaves behind a profound legacy in both business and philanthropy,” Bakish said. “ViacomCBS will remember Sumner for his unparalleled passion to win, his endless intellectual curiosity, and his complete dedication to the company. We extend our deepest sympathies to the Redstone family today.”

Though buffeted in the past decade by physical decline, succession battles and warring ex-girlfriends, Redstone in his day was a business juggernaut and once the richest man in entertainment.

Through his prescient confidence in the future of cable TV, Redstone built Viacom — and himself — into a powerhouse.

“Viacom is me, and I am Viacom,” he was famous for saying.

Under the Viacom umbrella, Redstone grew some of America’s favorite entertainment brands, including Paramount Pictures, Showtime, Comedy Central, MTV, VH-1, Nickelodeon and the Blockbuster video chain.

In 1999, he added the Tiffany Network to his holdings. The $37 billion merger with CBS catapulted Redstone from the business pages onto the public stage at age 76.

Behind it all was his love of great entertainment, encapsulated in his credo: “content is king.”

“Sumner Redstone was one of the great media moguls of the 21st century,” said his biographer, Keach Hagey.