Robert Parris Moses, a civil rights and voting rights pioneer, has passed away. According to his wife, Dr. Janet Moses, the educator and activist died on Sunday morning (July 25) in Hollywood, Florida. He was 86 years old.

Moses, who was widely referred to as Bob, was most known for his work with the Student Nonviolent Coordinating Committee (SNCC), which he joined as the Mississippi field director in 1960. In 1964, Moses launched the “Freedom Summer” project, which brought together hundreds of volunteers with a goal to register as many Black voters in Mississippi as possible to fight against the effects of voter suppression and Jim Crow.

While trying to register Black voters in Mississippi’s rural Amite County, Moses was beaten and arrested. He filed an assault charge against his attacker, but the man was acquitted by an all-white jury. In 1963, Moses and two other activists were also shot at in Greenwood, Mississippi.

Moses was also instrumental in the creation of the Mississippi Freedom Democratic Party, which sought to challenge the all-white Democratic delegation in the state.

In 1982, he began what he called his “second chapter in civil rights work” by founding the Algebra Project to improve math literacy among underserved populations. Moses also worked as a teacher in Tanzania, Africa and taught math in Massachusetts and Mississippi.

“Bob Moses was a hero of mine. His quiet confidence helped shape the civil rights movement, and he inspired generations of young people looking to make a difference,” Former President Barack Obama reacted to Moses’ passing on Twitter. “Michelle and I send our prayers to Janet and the rest of the Moses family.”

“Today, the world lost a giant. Bob Moses charted the path for teacher-activists to follow,” New York Congressman Jamaal Bowman wrote. “He showed us that democracy must start with loving & connecting with the ignored — and that they have the power to lead themselves. I pray that we will continue to follow his example.”

See their tweets below.