The colonial history of the United States has provided the basis for the nation's current race relations. As European colonial empires expanded in the late fifteenth and early sixteenth centuries, European constructions of race were spread globally. The concepts of race and racial hierarchies were developed as a means to justify emerging forms of exploitation during the colonial era. These emerging social constructs provided a framework for societies to categorize individuals and subsequently place them within a hierarchy—typically seen with what is defined as ‘white’ at the top and ‘black’ at the bottom. Professor of sociology, G. Reginald Daniel elaborates that these systems were ultimately constructed and employed as a means by which the practice of enslaving Africans could be defended.