Theory:Doctor Who television discontinuity and plot holes/The King's Demons


 * What happened to the desire Turlough expressed to return home at the end of Enlightenment?
 * He could have had a change of heart, the Doctor might not have been able to steer the TARDIS back to Trion during the right era, or there was an intervening, untelevised adventure where they did make it back, but Turlough decided to stay with the Doctor for the time being.
 * At the end of episode 2, Turlough does actually remind the Doctor that they're meant to be trying to take him home. The Doctor, however, overrides this destination, replacing it with the Eye of Orion.


 * Much of the history in this story doesn't make sense or is wrong
 * History isn't always exactly the same in the Whoniverse as in the real world. In fact, it sometimes changes (otherwise, there'd be no point to the story), so it isn't even exactly the same in the Whoniverse as it was earlier in the Whoniverse. (Some of the differences could even be ripple-effects of the fact that the Master has already affected things before the Doctor arrives, although not most.)


 * The Master's iron maiden TARDIS has an anachronistic Elizabethan ruff.


 * Sloppy use of the chameleon circuit by the Master. The locals wouldn't have realized it as anachronistic, merely a little odd-looking of an iron maiden.


 * The Magna Carta's importance was fabricated in the 17th century: it achieved very little in the 13th century.


 * Taking into account the Master's ironic and smug smile when the Doctor proposes Magna Carta as the reason for his scheme, it might well be that the Master was after something much more interesting and neglected to tell what it was.
 * The disruption of the Magna Carta would have massive ramifications to the timeline of the Earth; it's relative importance to the 13th century is somewhat beside the point. However, the absence of the Magna Carta would still have had the immediate effect of ending King John's rule.


 * French was still the language of the court in the early 13th century, so why does only Sir Gilles speak it?


 * Logically, with the Doctor's translation circuit, everybody, even Sir Gilles, should be speaking a language that the Doctor and/or his companions can naturally understand. It is possible that we hear French because the Doctor can actually speak French without the assistance of the translation circuits.


 * What was the Master's actual goal? How was he going to personally profit from the scheme?
 * It's unclear. But the Doctor himself recognizes it as unusually "small" for the Master. So it's not strictly a plot hole, as the script does describe it as an oddity.