Until this point, Dr. Martin Luther King, Jr. had yet to take part in these marches. But, On August 5, 1966, King joined Al Raby, Mahlia Jackson, and about 500 open occupancy protests in a march destined for Marquette Park. During this event, an oppositional white mob of over 10,000 individuals gathered. Verbal abuse by this opposition escalated into physical violence. This included the infamous "rock throwing incident" where Dr. King was hit in the head behind his right ear by a baseball-sized rock causing him to fall onto one knee. King remarked he had never seen such hostility, even from southern demonstrations.
On August 17, Mayor Richard J. Daley and the leadership of the Chicago Freedom Movement began negotiations at St. James Cathedral in downtown Chicago. During this meeting, the city stated they would limit the extent of protests downtown. This in turn caused marches to move out to the suburbs. The group of leaders met for a final time on August 26th and agreed to end the open housing demonstrations without exception. This came In exchange for many new promises. The city of Chicago was to create new commitments to promote fair housing. In addition, the Chicago Estate Board pledged to drop its opposition to (the?) state open-occupancy law. Political, business and religious leaders would also support the creation of an organization to fight for open housing throughout the Chicago metropolitan area.
As part of this agreement, Dr. King agreed to cancel a march that had been scheduled for two days later. Following his departure from Chicago in 1967, Dr. King admitted the Summit Agreement did not address every issue he had hoped, but he walked away from the windy city knowing it was better than Northern counterparts such as Detroit, Philadelphia, and New York.