Doctor Who: Why Each Doctor Was Forced To Regenerate
When you're a Time Lord, getting a makeover is no easy task.
If you were to make a list of the most genius creative decisions in television history, the concept of regeneration would almost certainly make the cut.
The process by which Time Lords are able to cheat death by healing all their injuries, glowing like a street lamp, and then transforming their bodies, the idea of swapping out lead actors every couple of years effectively makes Doctor Who immortal, and its incredible 57-year legacy (and counting!) speaks for itself.
Across that legacy, we've seen the Doctor regenerate many, many times, and discounting fake-outs (like those seen in The Impossible Astronaut, The Stolen Earth, or The Lie Of The Land), this results in them changing their appearance from head-to-toe, going from old to young, tall to short, and recently, from male to female.
The reasons for these regenerations vary greatly from Doctor to Doctor, and no two have ever been exactly the same. So - from the First to the Twelfth - let's talk about the very end of each Doctor's tenure, looking at those final moments that forced them to undergo the life-changing (quite literally) process of regeneration.
13. The First Doctor (William Hartnell)
This is it - the regeneration that started it all.
The First Doctor met his end in the four-episode serial The Tenth Planet, which first aired all the way back in 1966. After the threat of the Cybermen has been nullified, the Doctor wanders back to his TARDIS, alone, with his constant battles and adventuring (and his great age) having taken their toll on his rather frail body.
The next time we see him, he falls on the floor of the console room and his face starts to glow: the first regeneration in the history of the show has begun.
Decades later, the 2017 Christmas special Twice Upon A Time gave us some more details about the First Doctor's regeneration, revealing that he squeezed in a final adventure with the Twelfth Doctor right before returning to the TARDIS.
Twice Upon A Time also revealed that the First Doctor didn't want to regenerate, a problem that the Twelfth Doctor is also facing in this episode. But together, they overcome this feeling and accept that it's time for them both to move on.