Pyrovilia was the home planet of the Pyroviles, which was one of the 27 planets the Daleks transported to the Medusa Cascade, and one of only three planets in this operation that were not taken from 2009. It was, instead, taken more than 2000 years earlier. The reason for the discrepancy was never actually revealed, although Davros may have been experimenting with his technology before taking all the planets at once from 2009. Presumably it was a hot and waterless world, as they intended the Earth to be after their invasion. (DW: The Fires of Pompeii)
By 2009, the disappearance of Pyrovilia was considered a cold case by the Shadow Proclamation. It was then discovered by the Doctor that the planet was stolen by the Daleks and put in the Medusa Cascade along with 26 other worlds. When the Doctor and his companions had defeated the Daleks and Davros they sent it back with all the rest of the planets to its rightful destination. This was one of the ones returned by Donna Noble. (DW: The Stolen Earth/Journey's End)
Behind the scenes
- Several scenes in The Stolen Earth and Journey's End show a large, orange and molten world that fits the description given to Pyrovillia in The Fires of Pompeii, but it is unknown if this world is actually Pyrovillia.