The cultural boundaries separating white Americans from other racial or ethnic categories are contested and always changing. Professor David R. Roediger of the University of Illinois, suggests that the construction of the white race in the United States was an effort to mentally distance slave owners from slaves. By the 18th century, "white" had become well established as a racial term. According to John Tehranian, among those not considered white at some points in American history have been: the Germans, Greeks, white Hispanics, Arabs, Iranians, Afghans, Irish, Italians, Jews, Slavs and Spaniards. Finns were also on several occasions "racially" discriminated against and not seen as white, but "Asian". The reasons for this were the arguments and theories about the Finns originally being of Mongolian instead of "native" European origin due to the Finnish language belonging to the Uralic and not the Indo-European language family.