Jacob Grimm was a prominent German scholar and author in the 19th century. Along with his brother Wilhelm, he is best known as the co-author of the collection of folk tales and fairy stories known as Grimms' Fairy Tales. Grimm was a linguist and philologist who formulated Grimm's law, a set of rules describing the systematic sound shifts that occurred between Proto-Indo-European and the early Germanic languages. He also authored works on German mythology and lexicography, including the Deutsches Wörterbuch, a comprehensive dictionary of the German language. Grimm and his brother were influential figures in the Romantic movement and the development of modern folklore studies.