Carl Wilhelm von Sydow

In 1907 he published Våra folkminnen—Folksaga, folksägen, folktro (Our Folklore—Folktale, Legend, and Folk Belief) and participated in the founding of the Federation of Folklore Fellows' Communications in Copenhagen.

[6] In the 1930s he was a founder member of the Nazi-sympathising Riksföreningen Sverige–Tyskland [sv] (National Swedish-German Association) and served as vice president, but in April 1940 he resigned his membership.

[7] In addition to his publications on folklore, von Sydow contributed to the establishment of methodical study in the field in Sweden,[1] and his work was influential in other countries, particularly Ireland;[4][8] beginning with Tors färd till Utgård (Thor's Journey to Útgarð), one of his areas of particular interest was Celtic influence in Germanic folklore and literature, and Irish Gaelic was among several languages he learnt in adulthood and one he taught at Lund in the 1920s.

[3] An early interest in botany and zoology caused him to take a scientific approach to folklore study: in 1927 he originated the concept of the oicotype or ecotype, a form of a folktale which arose in adaptation to local circumstances,[2][3][4][9] and suggested several other terms, such as dite (a saying) and memorate (a personal narrative, usually concerning a supernatural encounter).

[2][3] He also came to repudiate the Finnish School in folklore studies as atomistic; he focussed on the transmission of folktales between individuals, for example drawing a distinction between 'active' and 'passive' tradition carriers or bearers (tale tellers and audience members).