“It is with enormous sadness that the Gregory family confirms that their father, comedic legend and civil rights activist Mr. Dick Gregory departed this earth tonight in Washington, D.C.,” his son, Christian, wrote on Instagram.

Gregory, who lived in Washington, died of heart failure in Sibley Memorial Hospital, where he had checked in a week ago after falling ill, said his longtime publicist Steve Jaffe.

Gregory’s success as a comedian in the early 1960s helped pave the way for other black comics, such as Richard Pryor, to gain greater fame by reaching a mainstream audience.

Born in St. Louis, Gregory grew up in poverty. He was working for the U.S. Postal Service and performing in front of largely black audiences for low pay when Playboy founder Hugh Hefner saw his act and hired the comedian to perform at his nightclub in 1961.

At the time, stand-up comedy was largely segregated.