Flavius Theodoric or Flavius Theodoricus was "King of the Ostrogoths, regent of the Visigoths and ruler of Italy". He was also known as Thiudareiks and some called him simply Didrik. He met the Fifth Doctor, Nyssa and Tegan twice during his life: once as a small boy and hostage of Emperor Leo of Constantinople and once when he was forced to kill Odoacer. (PROSE: Goths and Robbers)
Theodoric the Great was used in a guessing game by the Thirteenth Doctor, Graham, Yasmin Khan and Ryan Sinclair. His name was fixed to Ryan's forehead. (PROSE: The Shadow Passes)