• Media mogul Sumner Redstone was worth an estimated $3 billion at the time of his death
  • His net worth peaked at $5 billion in 2015
  • Redstone grew his business empire through aggressive acquisition tactics

Media legend Sumner Redstone, whose business empire included Viacom and CBS, passed away on Tuesday at the age of 97. The cause of death has not been revealed.

The businessman, whose net worth peaked at $5 billion in 2015, had an estimated net worth of $3 billion at the time of his death, according to Forbes. Redstone was no. 179 in the Forbes 400 list in 2019 but dropped to 804th on the magazine's billionaires list this year.

Redstone entered the media industry in 1954 when he joined his family's drive-in movie theater business, National Amusements. The next few decades saw him turning the business into a multi-billion dollar cinema and media empire.

In 1987, Redstone purchased Viacom in a hostile takeover for $3.4 billion and later spent $10 billion for Paramount in 1994, Fortune reported.

In 1999, Viacom swallowed CBS for $35.6 billion, but the merger broke apart in 2005.

CBS and Viacom agreed to merge last year, and Redstone was among the directors voting in its favor.

Today, ViacomCBS owns a number of media brands such as the CBS Television Network, CBS News and 15 CBS-owned TV stations. Paramount Pictures, publisher Simon & Schuster and cable channels such as BET, Comedy Central, MTV, Nickelodeon and Showtime also fall under its umbrella.

His aggressive acquisition tactics earned him the reputation of being a ruthless businessman, but his instincts helped him to play a role in shaping the landscape of the modern entertainment industry.

"In 1987, when I purchased Viacom, it was a struggling cable television programming venture with a few undeveloped and overlooked assets that everyone encouraged me to sell," Redstone said in a speech at Boston University in 2007.

"You know, they said that MTV was a fad," he added. "They said that Nickelodeon could never make it because who was interested in a kids' channel … in your life, in the final analysis, you have to follow your own instincts."

As for the secret to his success, Redstone said it was impatience.

"Patience is a virtue that I do not respect," he said in a 2012 interview with CNBC. "If you’re patient, you’ll never go anywhere. It takes impatience to drive you to succeed."

He was also an avid philanthropist, contributing more than $216 million to charities around the world, according to the Sumner M. Redstone Charitable Foundation.

In a statement following his death, ViacomCBS chairman Shari Redstone, the mogul’s daughter, hailed him for having led an "extraordinary life," CNBC reported.

"[Redstone] not only shaped entertainment as we know it today but created an incredible family legacy," his daughter said. "Through it all, we shared a great love for one another and he was a wonderful father, grandfather and great-grandfather. I am so proud to be his daughter and I will miss him always."

Redstone is also survived by a son, Brent.

The media mogul was married and divorced twice, first to Phyllis Gloria Raphael, who is the mother of his children, and then to schoolteacher Paula Fortunato.

Sumner Redstone, the media mogul who led an empire that included ViacomCBS, is seen in 2007 -- he has died at the age of 97
Sumner Redstone, the media mogul who led an empire that included ViacomCBS, is seen in 2007 -- he has died at the age of 97 AFP / HECTOR MATA