When I originally wrote The Hall of Lost Souls - story number 14 - it was meant to be a one off story. But midway through the series I decided I WAS going to have The Doctor's son restored to him and the Lost Souls immediately struck me as a perfect solution to the puzzle. Hints were seeded. The first was in the Rassilon's Envelope story in which The Doctor first wonders whether his son might not be dead, but dismisses it as too much to hope for. The next clue is in Millennium Man, when The Doctor is told, by the ghost of his first wife, that their son is a lost soul. His father's ghost, later, in Misunderstandings, gives him a further push in the right direction and it finally dawns on him.

And so he returns to the Hall of Lost Souls and demands to know where his son is. This part was written quite a long time in advance of the rest of the story. The sequence in which he plants a memory in the shell of the old man who he finds there, and carrying him back to the TARDIS.

The SangC'lune sequence was written about four months after the Hall of Lost Souls sequence, but the two fitted perfectly easily together. The question of how to get into his son's pyramid actually caused me some problems. But it gave an excuse for The Doctor to go into his own pyramid and talk to his other selves once more.

And then the long night in which The Doctor and his son talk things over between themselves. How many conversations have taken place on this veranda now? In the first two SangC’lune stories The Doctor and Rose sit there and talk. In the third, The Doctor and Jackie have a heart to heart. Then Rose and Wyn in Mindflip. Finally, The Doctor and his son. It occurs to me that I need a Doctor Jack sequence to take place there.

And so, back home to Richmond upon Thames in the 23rd Century, and an emotional reunion for Susan and her father, which is, in fact, played down somewhat because the scene switches quickly to Rose and The Doctor in the garden. This scene was ALSO written several months before the whole thing was put together. This was originally going to be the final scene of the final story in the series. The Doctor is taken by Rassilon and shown his future, told that he will be the patriarch of the new race of Time Lords living on Earth and being granted the solution to his and Rose’s overriding issue. Yes, she will be able to bear him children. And what is more, having given up his remaining lives to her the two of them will live the length of an ordinary Gallifreyan life together. A happy ending.

By the time I came to put it all together it was clear that readers wanted to see their actual wedding. When it went online, I WAS inundated by letters from distraught fans who thought it WAS the end and had to reassure them that there WERE several more stories to come.

And ONE letter from a reader who told me that I had written a biblical analogy. Rassilon taking The Doctor up to the heavens to show him the future before him is actually very close to the Old Testament story of Jacob’s Ladder or Jacob’s Dream, in which Jacob, sleeping in the wilderness with a stone for a pillow, is taken up in a dream and God tells him that his children will be numerous and that they will be the chosen people – Jacob is the father of the Israelites. Now, its actually a while since I read that part of the Old Testament, and I don’t remember it ever having much of an impact on me. So the analogy was not in any way deliberate. But having looked it up, I realised that I HAD written an Old Testament analogy. And then I recalled that Jacob’s Pillow or Pillar was reputed to be the Stone of Destiny that is allegedly hidden with the Ark of the Covenant and David’s Harp in the Hill of Tara – which brought us back to one of the very EARLIEST stories in the series, Vampyre of Tara. Since I was already planning the follow on series, New Lords of Time, there was a rich thread to follow from this happy accident.

But there it is. Not the end. But the beginning of the end of the Unfinished Business.

http://en.wikipedia.org/wiki/Jacob's_Ladder

http://www.pearsecom.co.uk/doctorwho/05vampyres.htm

http://www.pearsecom.co.uk/doctorwho/14lostsouls.htm