On May 8, 1965, a group of musicians gathered at a house on the South Side of Chicago. They’d been summoned there, via postcards mailed out by four local peers, to discuss the founding of a new collective, devoted to generating fresh opportunities for artists engaged in what they called, simply, “creative music.” At one point during the meeting, a saxophonist named Gene Easton summed up the frustrations shared by many in attendance.

“We’re locked up in a system,” he said, “and if you don’t express in the system that is known, you’re ostracized.” “But,” he added, “there are far better systems.” By this time, some prominent musicians had famously bucked mainstream jazz conventions, pursuing revolutions either subtle or splashy (see ’ and ’s , respectively).

But change in jazz still came with controversy: , for example, was alienating some critics and peers with an increasingly abstract style. For an average working jazz musician, especially outside the hotbed of New York, who wanted to keep gigging while also aspiring to engage with vanguard sounds—let alone one, who like some present at that 1965 South Side meeting, was wary of pledging allegiance to jazz, or any other style—it’s easy to see why open expression still felt risky. When Easton spoke of feeling “locked up,” he was talking in musical terms.

But his desire to transcend creative restriction signified a higher purpose for the nascent Chicago collective, one that would open up .