How a funky Harlem music fest became the ‘Black Woodstock’

When Freddie Stone, Sly’s brother, played the Harlem Cultural Festival as guitarist and co-founder of Sly and the Family Stone in the summer of 1969, it was not yet known as the “Black Woodstock,” as it would be christened in later years. “We didn’t know that it was going to turn out to be the…