Physically, it was situated at the base of Mount Cadon, Gallifrey's highest peak. An imposing structure, it was a dark, ebony building (PROSE: Timewyrm: Revelation, Lucifer Rising) at the northern border of "southern Gallifrey". (PROSE: Lucifer Rising) As Lord President, the Doctor was able to access its so-called "black collection" and steal a portable temporal link. (PROSE: Timewyrm: Revelation)