After leaving the Tuskegee Institute, Park joined the University of Chicago where he developed a theory of assimilation, as it pertained to immigrants in the United States, known as the "race relation cycle". The cycle has four stages: contact, conflict, accommodation, and assimilation. The first step is contact followed by competition. Then, after some time, a hierarchical arrangement can prevail – one of accommodation – in which one race was dominant and others dominated. In the end assimilation occurred. Park declared that it is "a cycle of events which tends everywhere to repeat itself" and that it can also be seen in other social processes." He was instrumental in founding the race relations course at Chicago.