Minyos

Minyos was the homeworld of the Minyans. It was an Earth-like planet discovered by the Time Lords early in their space-time exploration, and they advised the Minyans as gods for centuries before the Minyans rose up and attacked every Time Lord base, killing many. (PROSE: Doctor Who and the Underworld)

After driving out the Time Lords, the Minyans developed further technology, including nuclear weapons which they used to cause a nuclear war that split the planet, (TV: Underworld) leaving only a field of asteroids for the Time Lords to discover. (PROSE: Doctor Who and the Underworld) In reality, Minyos was accidentally destroyed by a Time Lord Timonic Fusion Device, with the civil war story disseminated as a cover. (AUDIO: The Inquiry)

A Minyan ship, the R1C, survived the destruction and joined together with the descendants of another Minyan ship, the P7E, to colonise Minyos II, (TV: Underworld) in the neighboring system to Minyos. (PROSE: Doctor Who and the Underworld)

Behind the scenes

 * Many of the names and incidents in Underworld were derived from the myth of Jason and the Argonauts. In Greek mythology, the were the original inhabitants of the Mediterranean. In some versions of the Jason myth, the Argonauts are referred to as "Minyans" because Jason's mother was descended from the Minyans.
 * The reference book The Discontinuity Guide speculates, based on his knowledge of Gallifrey, that Dastari hailed from Minyos or Dronid. (TV: Shada)