By 1902 the German archaeologist Gustaf Kossinna identified the original Aryans (Proto-Indo-Europeans) with the north German Corded Ware culture, an argument that gained in currency over the following two decades. He placed the Indo-European Urheimat in Schleswig-Holstein, arguing that they had expanded across Europe from there. By the early 20th century this theory was well established, though far from universally accepted. Sociologists were soon using the concept of a "blond race" to model the migrations of the supposedly more entrepreneurial and innovative components of European populations.