Von Sydow was appointed a lecturer in Nordic and comparative folkloristics at Lund University in September 1910, In April 1940 he was awarded a personal
chair. He was a pioneer of radio lecturing, beginning in 1926. In the 1930s he was a founding member of the Nazi-sympathising (National Swedish-German Association) and served as vice president, but in April 1940 he resigned his membership. In addition to his publications on folklore, von Sydow contributed to the establishment of methodical study in the field in Sweden, 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. and suggested several other terms, such as dite (a saying) and memorate (a personal narrative, usually concerning a supernatural encounter). Starting in the 1920s, he came to regard many supernatural beings and customs in modern folk belief as ficts, fanciful explanations often meant to manage children by creating a
bogeyman, and therefore came into conflict with other scholars' religio-historical theories, such as
Wilhelm Mannhardt's analyses of harvest customs. 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). ==Personal life==