August Johann Gottfried Bielenstein was a Baltic German linguist, folklorist, ethnographer, and theologian.

Wilhelm Mannhardt was a German mythologist and folklorist. He is known for his work on Germanic mythology, on Baltic mythology, and other pre-Christian European pantheons; and for his championing of the solar theory, namely in the early years of his career, under the influence of Jakob Grimm. Later on, Mannhardt focused more on vegetation spirits from an evolutionist point of view, namely the primitive tree cult and its later developments.