Claudia Roth Pierpont's "Black, Brown, and Beige" is a review of several recent books about Duke Ellington, but it concludes with an image of Charles Mingus that brought tears to my eyes:

Two years before Ellington died, in 1972, Yale University held a  gathering of leading black jazz musicians in order to raise money for a  department of African-American music. Aside from Ellington, the  musicians who came for three days of concerts, jam sessions, and  workshops included Eubie Blake, Noble Sissle, Dizzy Gillespie, Charles  Mingus, Max Roach, Mary Lou Williams, and Willie (the Lion) Smith.  During a performance by a Gillespie-led sextet, someone evidently  unhappy with this presence on campus called in a bomb threat. The police  attempted to clear the building, but Mingus refused to leave, urging  the officers to get all the others out but adamantly remaining onstage  with his bass. “Racism planted that bomb, but racism ain’t strong enough  to kill this music,” he was heard telling the police captain. (And very  few people successfully argued with Mingus.) “If I’m going to die, I’m  ready. But I’m going out playing ‘Sophisticated Lady.’ ” Once outside,  Gillespie and his group set up again. But coming from inside was the  sound of Mingus intently playing Ellington’s dreamy thirties hit, which,  that day, became a protest song, as the performance just kept going on  and on and getting hotter. In the street, Ellington stood in the waiting  crowd just beyond the theatre’s open doors, smiling.

Who else but Mingus would have come up with an act like that? Well, maybe Charlie Haden, who dedicated "Song for Che" to freedom fighters in Angola and Mozambique while performing in Lisbon in 1971. See here for his version of the story.