Joseph Shabalala, founder of the a cappella South African vocal group Ladysmith Black Mambazo that shot to international fame after recording with Paul Simon, died in Pretoria at the age of 78. No cause has been announced.

The group wrote on Facebook, “Our Founder, our Teacher and most importantly, our Father left us today for eternal peace. We celebrate and honour your kind heart and your extraordinary life. Through your music and the millions who you came in contact with, you shall live forever.”

Shabalala formed the group that would become Ladysmith in the early 1960s, singing isicathamiya, which was developed by workers in South Africa’s diamond mines. They made their first of more than 60 records in 1973 and by the end of the decade, they were among the country’s most popular singing groups.

Simon used the group on his Graceland album in 1986—they sang on “Homeless” and “Diamonds on the Soles of Her Shoes”—and toured the world with him. Simon then produced Ladysmith’s first international release, Shaka Zulu, which would win a Grammy in 1988. The group has been nominated for 17 Grammys, winning five.

Shabalala and his group recorded with Dolly Parton, Emmylou Harris, Josh Groban and others. A favorite of Nelson Mandela, they sang for him at the Nobel Peace Prize ceremony and at his inauguration.

Shabalala retired from Ladysmith Black Mambazo in 2014 and five of his sons are currently in the group.

The Economic Freedom Fighters party said i the group’s “music spoke to the social realities of black cultural norms and traditions, and was able to bring to light the social conditions of black South Africans.”