German philologist and folklorist Jakob Ludwig Karl Grimm in 1822 formulated Grimm's Law, the basis for much of modern comparative linguistics. With his brother Wilhelm Karl Grimm (1786-1859), he collected Germanic folk tales and published them as Grimm's Fairy Tales (1812-1815). Indo-European stop consonants, represented in Germanic, underwent the regular changes that Grimm's Law describes; this law essentially states that Indo-European p shifted to Germanic f, t shifted to th, and k shifted to h. Indo-European b shifted to Germanic p, d shifted to t, and g shifted to k. Indo-European bh shifted to Germanic b, dh shifted to d, and gh shifted to g. This jurist and mythologist also authored the monumental German Dictionary and his Deutsche Mythologie . Adapted from Wikipedia.