Russell T Davies' imminent return to Doctor Who has fans excited for new stories from one of the series' most beloved writers. As the showrunner who relaunched the classic sci-fi series back in 2005, Davies had one of the toughest jobs of any of Doctor Who's head writers and succeeded in restoring the series to its status as one of the BBC's flagship brands. His return comes at a time when fan opinion of the series, now helmed by Chris Chibnall, is perhaps more divided than ever before in its modern run. With recent storylines proving controversial, Davies' return has raised questions around the future direction of Doctor Who.

In particular, the history of the so-called Timeless Child, which was first referenced in Season 11, Episode 2, "The Ghost Monument," and later fully explored in the Season 12 finale, "The Timeless Children," struck some sections of the fanbase as a plot twist too far. This revelation opened the door to a brand new secret origin for the Doctor, but there have been calls from some fans for Russell T Davies to retcon the plotline. However, a closer look at Davies' previous work on Doctor Who reveals exactly why he won't undo this divisive story arc.

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Christopher Eccleston and Billie Piper in 2005's Doctor Who

Season 12's finale revealed the true nature of the Doctor's species, the Time Lords, and the secret significance of the Doctor in their history. The episode saw the Master unlocking secrets the Time Lords had tried to bury, revealing that they gained the ability to regenerate from a child of unknown origin, discovered on a mysterious, distant world by the Gallifreyan explorer, Tecteun. From this "Timeless Child," who regenerated instead of dying, Tecteun helped Gallifrey's society evolve into Time Lords, imbuing them with the power of regeneration. And that child was the Doctor.

The reveal added a brand new chapter to the Doctor's history, revealing they had lived many lives before becoming the first Doctor seen by audiences in 1963. The Doctor spent their forgotten lives serving as an operative for a clandestine Time Lord organization simply called the Division, before having their memory wiped and being returned to childhood to begin their "first" regeneration cycle. While the story added much to the Doctor's backstory without undoing any of the show's rich history, there were still some fans who viewed it as a retcon and who may be hoping to see Davies strike this chapter from Who history.

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There's an issue here, though. Chris Chibnall is hardly the first Doctor Who writer to add a major new chapter to the history of the Time Lords and the Doctor. When he took up the reins to the show in 2005, Davies made one key change to the Doctor -- unlike in the classic series, the Doctor was now the last of the Time Lords. The reveal first came in Episode 2 of Season 1, "The End of the World," and was expanded upon throughout the series, with it being revealed that the Time Lords had fought the Daleks in the Time War, a conflict the Doctor ended by wiping out both sides. For the first time since their introduction to Doctor Who canon in 1969's "The War Games," the Time Lords were killed off and removed from the series.

Davies is not one to shy away from shaking up the status quo. His big change to Doctor Who canon was actually not too dissimilar to Chibnall's. Both the Time War and the history of the Timeless Child added to the Doctor's existing backstory, both sought to recapture the image of the Doctor as a unique but lonely figure in the universe, and crucially, both restored some mystery to the Doctor's past.

When Doctor Who began in 1963, precious little was revealed of the Doctor's history -- it wasn't even clear if the Doctor was an alien or a human from the far future. Bit by bit, the mystery was blown away, with more of the Doctor's origins as a rebellious Time Lord revealed over the decades. When the series was relaunched in 2005, the events of the Time War, the Time Lords' deaths and the Doctor's role in it all were only hinted at initially -- again, it took years for the mystery to be resolved. Now, the Timeless Child has introduced a whole new era to the Doctor's life, abundant in fresh mysteries to be explored. With Chibnall's tenure coming to an end soon, it is unlikely Davies will want to undo a twist that puts the "Who?" back in Doctor Who.

Doctor Who Season 13 will premiere on Oct. 31 on BBC and BBC America.

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