What conditions are believable for a racial society majority to accept a racial minority, and those to reject them?
I have two races. One is a racially pure majority and the other is a mixed breed minority. In one time frame, the majority accepts and shelters the minority, and then in a later time frame the majority enslaves the minority. I am at a loss on what conditions would allow these turn of events to happen of which are believable. Any suggestions? In the end of the story, the racial majority are punished for their crimes.