Brothers Grimm

Jacob Grimm and Wilhelm Grimm, known together as the Brothers Grimm, (AUDIO: L.E.G.E.N.D.) were linguists and, according to Bernice Summerfield, the writers of Grimms' Fairy Tales — not the Just So stories as Keri thought. (AUDIO: Buried Treasures) They developed the Law of Consonantal Shift, which stated that language changed over the course of centuries due to how the pronunciation of words changed. The Fourth Doctor brought this up to Romana II when discussing how the names of the Hydrax officers had changed to Aukon, Camilla and Zargo. (TV: State of Decay)

Sarah Jane Smith thought of their fairy tales when looking at the Black Forest. She expected to find a werewolf, a witch, Hansel and Gretel, the Little Red Riding Hood, and the Big Bad Wolf. (PROSE: Managra)

Evelyn Smythe compared Sancreda to something out of Grimms' Fairy Tales. (AUDIO: The Spectre of Lanyon Moor)

According to the Twelfth Doctor, the Brothers Grimm were on the Doctor's darts team. They also told a story about the shepherd's boy, who was asked by an emperor how many seconds there were in eternity. The Doctor repeated this story to the Veil as the Doctor died and got copied by the teleporter again and punched at the wall of azbantium inside his confession dial in a repeating cycle (TV: Heaven Sent) of about 4.5 billion years. (TV: Hell Bent)

On their first adventure together, while trapped in the Cave of Skulls, Barbara Wright told the First Doctor the story of "Godfather Death" by the Brothers Grimm. The Eighth and Ninth Doctors would later recount the tale to Brian the Ood and Rose Tyler, respectively. (PROSE: The Knight, The Fool and The Dead)