Renowned singer and activist Harry Belafonte died Tuesday at age 96. He was known for topping pop charts, acting on Broadway, breaking racial barriers and marching in the civil rights movement alongside Martin Luther King Jr.

The cause of death was listed as congestive heart failure, a longtime spokesman for Belafonte told The New York Times.

Belafonte rose to fame during a time of intense racial segregation, and used his influence as a Black entertainer to push for change.

According to the Times, Belafonte “almost single-handedly ignited a craze for Caribbean music with hit records like ‘Day-O (The Banana Boat Song)’ and ‘Jamaica Farewell.’” His album “Calypso,” that featured both of those hit singles, topped the Billboard charts in 1956 and stayed at the top for 31 weeks.

Shortly after his musical success, he also found success in Hollywood acting as a leading man. But following his rise to success in the 1950s, Belafonte turned his focus to civil rights and activism.

He became a close friend to King and wanted to use his platform to help others after growing up as the son of a poor Jamaican mother who made money for the family by working as a domestic servant.

“The portion of my life that is of importance to me has to do with my activism,” Belafonte told The Dallas Morning News in 2011. “I’ve often responded to queries that ask, ‘When as an artist did you decide to become an activist?’ My response to the question is that I was an activist long before I became an artist. They both service each other, but the activism is first.”

Some of his efforts include leading a campaign against apartheid in South Africa, as well as helping raise money for the civil rights movement with King and meeting with key leaders to gain support for the movement.

At one point, Belafonte and fellow actor Sidney Poitier journeyed to Mississippi in order to deliver a bag carrying $70,000 supporting voter registration efforts. He said on the journey they “were chased and shot at by the Ku Klux Klan but eventually succeeded in hand-delivering their money,” CNN reported.

In later years, he was crucial to the fight against HIV/AIDS and came up with the idea for the song “We Are the World,” which brought together a group “of pop and rock stars, including Bob Dylan, Michael Jackson and Bruce Springsteen, to raise money for famine relief in Africa,” per CNN.

The NAACP awarded him the organization’s highest honor, the Spingarn Medal, in 2013 for his efforts to support justice and equality, per CNN.

“America has never been moved to perfect our desire for greater democracy without radical thinking and radical voices being at the helm of any such quest,” Belafonte said when he accepted the award, per Democracy Now.

What are people saying about Harry Belafonte?

Activists, entertainers, politicians and fans of Belafonte outpoured their gratitude for his work and influence after hearing about his death. Here are some of the notable people who tweeted about him.

“After dad was assassinated, Harry Belafonte joined me, mom, and my siblings in Memphis. He was one of the only people to make sure that mom and her children were taken care of in the months, days, and years after the assassination. He was there for us even when others had gone,” Martin Luther King III tweeted.

“Today we honor and remember the life of our friend, Harry Belafonte. Take a moment with us to reflect and honor his legacy and enjoy this Sesame Street classic,” Sesame Street tweeted.

“RIP to my dear brother-in-arms, Harry Belafonte. From our time coming up, struggling to make it in NY in the 50’s with our brother Sidney Poitier, to our work on ‘We Are The World’ & everything in between, you were the standard bearer for what it meant to be an artist/activist,” musician and humanitarian Quincy Jones tweeted.

“Harry Belafonte was a barrier-breaking legend who used his platform to lift others up. He lived a good life — transforming the arts while also standing up for civil rights. And he did it all with his signature smile and style. Michelle and I send our love to his wife, kids, and fans,” former President Barack Obama tweeted.

“Harry Belafonte was one of our favorite guest stars on The Muppet Show and a great friend to The Muppets. In his work on and off the stage, he helped us all to see one another clearly and truly turned the world around. We will never forget you, Harry!” The Muppets tweeted.

“Harry Belafonte was not only a great entertainer, but he was a courageous leader in the fight against racism and worker oppression. Jane and I were privileged to consider him a friend and will miss him very much,” Sen. Bernie Sanders tweeted.

“Harry Belafonte epitomized what the role of an artist should be. The voice that brings together the community to engage each other in the exercise of self determination, the declaration of that society’s values, and in doing that inspire the society to action. A man of conviction,” actor Wendell Pierce tweeted.

“Harry Belafonte was one of our nation’s most powerful voices for change. America has lost a giant. Doug and I are praying for his family and loved ones,” Vice President Kamala Harris tweeted.

“I am deeply sad at the loss of my very dear brother — the great Harry Belafonte! His artistic genius, moral courage & loving soul shall live forever! God bless his precious family!” activist Cornel West tweeted.