Karn

Once a colony of Gallifrey, 'Karn would later serve as the home of the powerful the Sisterhood and bolthole of the Time Lord criminal Morbius.

Characteristics
The Doctor stated that he was born on Karn, then corrected himself to say near Karn. (DW: The Brain of Morbius).


 * By implication, Karn resided near Gallifrey, as well as having a known importance place in the history of Gallifrey and of the Time Lords.

Early History
Karn was originally a colony of the old Gallifreyan Empire which existed in the days before Rassilon. The Sisterhood of Karn were a remnant of the Pythias who once ruled Gallifrey before being expelled by the triumvirate of Rassilon, Omega, and the Other. (NA: Cat's Cradle: Time's Crucible

Modern History
In the Rassilon Era, the Sisterhood guarded the Sacred Flame. The Sacred Flame is used to distill the Elixir of Life, which can aid a Time Lord who is experiencing difficulty with regeneration. (DW: The Brain of Morbius)

The planet, appears to be (during Morbius's attempted re-birth) a barren, rocky wasteland, littered with the wreckage of crashed spaceships. (DW: ''The Brain of Morbius

Apocryphalinformation
The Crystal of All Power, sought by the the Doctor and the Daleks resided on Karn. (T: The Seven Keys to Doomsday)

Behind the Scenes
Karn originated in a theatrical play, The Seven Keys to Doosmday, written by Terrance Dicks. He later re-used the name when writing the script for The Brain of Morbius. The play featured a non-canonical Fourth Doctor played by Trevor Martin. The presence of this other Fourth Doctor would make the play difficult to integrate into known continuity. The Doctor does not make reference to these earlier events on Karn in any other story.