Charles J. Ogletree Jr., a famed Harvard law professor and scholar, has died. He was 70.

“It is with a heavy heart that I share the news that our friend and colleague Charles Ogletree has passed away,” Harvard Law’s Dean John F. Manning said in a statement to the school Friday. “The Jesse Climenko Professor of Law Emeritus, Charles—or Tree, as he was affectionately known — lived a life of great consequence, achieving what few can even dream.”

Ogletree was a voice of reason who didn’t shy away from difficult discussions and was a mentor to former President Barack Obaman and many more.

He founded the Charles Hamilton Houston Institute for Race and Justice that became “a leading force for scholarship, advocacy, coalition building, education, and community engagement on civil rights and equal opportunity,” Manning said.

Ogletree revealed years ago he was diagnosed with Alzheimer’s disease.

“Courage and conviction defined our friend and colleague. He showed that not only throughout his storied career, but in the bravery and openness he demonstrated about the illness with which he struggled in his final years,” Manning said.

“I am grateful to Charles for the friendship and kindness he extended to me throughout our years together on this faculty. He had a way of teaching not just his students, but his friends, that was powerful, decent, and giving — that without judgment helped you edge always a little closer to the best version of yourself.”

Funeral arrangements were not immediately available.