Doppelganger introduced a new friend for Chrístõ. Originally is was going to be a new enemy. The idea of an exact double of himself who would be the opposite of him in temperament was going to be the idea, and initially Penne Dúre seems a rather unpleasant type. Chrístõ’s friends are all set against him, and his history doesn’t bode well for him.

The idea that Penne would be a full blood Gallifreyan, but of a disgraced and exiled family, whereas Chrístõ, the half-blood, is still the son of an honoured and important family in Gallifreyan society seemed to me ironic given the future history of the Doctor as an exile. Penne and Li Tuo who we have already met represent something of a precursor of his own future.

The name was inspired by Peine forte et dure, a form of torture and execution used in Britain in the 16th and 17th century, especially against Catholics. Several martyrs and saints were killed that way, most notably Saint Margaret Clitheroe of Lancashire, which is where I came across the term at the time when I was creating the new character. As a means of committing a horrendous crime I can’t think of a worse way. Quite HOW an entire family was killed using the Peine Forte machine described in the story it is probably better not to dwell upon. But suffice to say that Penne’s parents were not nice people.

But Penne, I decided in the end would break the mould. Under the influence of Chrístõ and his father he would change from lazy and disinterested to a good leader of his people. Would it have been better to have him as a villain? Well, on reflection, maybe not. We already have Epsilon as a pain in everyone’s backside. Yes, he will be back. An ally for Chrístõ with a planet of his own seemed more useful.

Yes, he does bear some resemblance initially to the emperor in the Citadel. For that reason the Lagenorhyncus story went between the two. But there are no plans to return to the Citadel whereas Penne is set to be a recurring character.

http://faculty.cua.edu/pennington/Law508/PeineForte.htm

http://www.newadvent.org/cathen/04059b.htm