Thule

Thule was the home of an Empire which a marauding Sphinx reigned over until it was overthrown by the Gallifreyan hero Prydonius. (PROSE: Cat's Cradle: Time's Crucible)

The Renegade Daleks had a base on Thule. Historians studying Dalek history found a damaged Supreme Dalek from the New Dalek Paradigm within the base, wondering if the Paradigm had interfered in the Imperial-Renegade Dalek Civil War. (PROSE: Dalek: The Astounding Untold History of the Greatest Enemies of the Universe)

Undercover Nazi agent Kriemhilde Steiner incorrectly believed that a phoenix egg uncovered near the Crystal Palace in London, 1936, was the "Eagle of ultima Thule". She believed it would bring the Third Reich great power, but when the phoenix hatched, it burned her to death before returning to its home dimension. (COMIC: The Eagle of the Reich)

The Academia Library on Gallifrey had a section dedicated to the "barbaric Empire of Thule". (PROSE: Cat's Cradle: Time's Crucible)