The Rev. Jesse L. Jackson, who led the U.S. Civil Rights Movement for decades, died Tuesday. The protege of the Rev. Martin Luther King Jr. and two-time presidential candidate was 84.

As a young organizer in Chicago, Jackson was called to meet with King at the Lorraine Motel in Memphis, Tennessee, shortly before King was killed, and he publicly positioned himself thereafter as King’s successor.

Jackson led a lifetime of crusades in the United States and abroad, advocating for the poor and underrepresented on issues, including voting rights, job opportunities, education and health care. He scored diplomatic victories with world leaders, and through his Rainbow/PUSH Coalition, he channeled cries for Black pride and self-determination into corporate boardrooms, pressuring executives to make America a more open and equitable society.

And when he declared, “I am Somebody,” in a poem he often repeated, he sought to reach people of all colors. “I may be poor, but I am Somebody; I may be young; but I am Somebody; I may be on welfare, but I am Somebody,” Jackson intoned.

It was a message he took literally and personally, having risen from obscurity in the segregated South to become America’s best-known civil rights activist since King.