In the late 19th century, the concept of an “Aryan” race proposed that the descendants of Indo-European language speakers constituted a distinct sub-race of Caucasians. Although originally intended only as a linguistic classification, proponents of white supremacism (e.g. Nazis) claimed that the Aryan race was a master race. In his 1922 book Rassenkunde des deutschen Volkes, racial theorist Hans F. K. Günther identified the Aryan race in Europe as having five subtype races: Nordic, Mediterranean, Dinaric, Alpine, and East Baltic, with Nordics being the highest in the racial hierarchy. Each racial subtype had physical (hair, eye, and skin color, facial structure) and certain emotional traits and religious beliefs. Adolf Hitler embraced the concept of Aryan Herrenvolk (master race) and believed that Jews and the vast majority of Slavs, who had dangerous non-Aryan Asiatic origins, were Untermenschen (subhumans).