before the modern age, no europeans thought of themselves as "white". instead, they defined their race, ancestry, or ethnicity in terms of their nationality: greek, roman, etc. the concept of a unified white race came into use in the 17th century, or later. the strongest proponents of racism in 20th century europe, fascist italy and nazi germany, regarded some european peoples such as slavs as racially different from themselves even though they are white.