The Time of the Doctor

The Time of the Doctor was the 2013 Christmas Special of Doctor Who. It was Matt Smith's final regular appearance as the series lead, but unusually it did not formally introduce his successor, since Peter Capaldi's Twelfth Doctor had already been seen in the previous episode.

The show's 800th episode — and the last produced by Marcus Wilson — it served as a conclusion to the entirety of the Smith era. It especially tried to give final relevance to the Silence, the cracks in time, Trenzalore and the salvation of Gallifrey. As such, it was a unique attempt at narrative conclusion for storylines running through the entirety of a particular incarnation's tenure. It also significantly aged the Doctor, establishing that the Eleventh Doctor had lived much longer than any other incarnation.

But it was especially important to the history of the programme because it addressed an issue that hadn't been talked about in the series since its return in 2005: the limited amount of regenerations in a Time Lord's regeneration cycle. This episode confirmed that the Tenth Doctor's aborted regeneration in Journey's End did indeed use up a whole regeneration, and with the retroactive introduction of the War Doctor in between their Eighth and Ninth incarnations this meant that the Doctor had no more regenerations left, leaving the Eleventh Doctor as the last incarnation in his regeneration cycle. However, the Doctor is granted a brand new regeneration cycle at the end of the story, drastically altering his fate. This is not only the first time that a new regeneration cycle has been given on screen but the depiction of a new regeneration cycle ensured that the programme would be able to continue and keep casting new actors in the role for potentially decades.

The necessity for this had previously been unclear. Some early episodes of the show had suggested the Doctor's lifespan was practically infinite. Even Matt Smith's Doctor seemed to hint at this possibility in an episode of The Sarah Jane Adventures. But other stories, starting with The Deadly Assassin, set the limit to thirteen lives. Time was the first episode of Doctor Who produced by BBC Wales to choose a side, confirming that a "regeneration cycle" indeed consisted of just thirteen incarnations.

The only way to do this, however, was to change some othercontinuity. From one perspective, getting the Eleventh Doctor to the magic number thirteen meant that no BBC Wales incarnation could technically be the number under which they were marketed. This had already been the case once The Night of the Doctor definitively showed the Eighth Doctor regenerating into the War Doctor. Time, however, incremented the number again, explicitly stating, as mentioned above, that the aborted regeneration shown at the conclusion of The Stolen Earth and the beginning of Journey's End "counted". This made the "Eleventh Doctor" the thirteenth life.

Nevertheless, writer Steven Moffat said in DWM 467 that the BBC marketing was also narratively correct: "I've been really, really quite careful about the numbering of the Doctors ... It's not a matter of counting the regenerations, but of counting the faces of the Time Lord that calls himself the Doctor."