@RobbyBevard:
Where DOES all the info about Rassilon come up anyway? I know he has a bajillion relics lying around, I've gotten the gist of things from various spots over time, but I'm still making my way through all the old stuff for the first time as an adult. I think I might like to skip ahead a little and check out the stories about him.
There's odd mentions of bits and pieces here and there but it's mostly drawn out in the comics, books and audios. Doctor Who "canon" as it were isn't as black and white as other sci-fi shows. Rassilon is pretty much never referred to in a negative sense in the TV show, quite the opposite infact. The Five Doctors portrays him as more of a wise old king, yet he gets portrayed as a villain and tyrant in almost every other continuity, a concept that is later brought on into the TV show in The End of Time. Theres actually loads of examples of spin-off stuff effecting the events of the show itself now.
Quite interestingly, this leads into some other stuff I've found while I've been listening to more and more Big Finish stories.
I know the golden rule is "if it's on TV then it's indisputable but if it's anything else then it's questionable" but that's not always the case with Doctor Who. It's more a case of if it fits and TV doesn't argue with it, then theres no reason for it not to be.
Quite a lot of the Big Finish audios are considered canon by Russell T Davies himself. We all know he counts the events of Genesis of the Daleks as an early move in the Time War but interestingly in the 2006 Doctor Who annual he counts the "Etra-Prime Incident" aka The Apocalypse Element (Dalek Empire pt 2) as one as well.
This story is one that introduces Romana's presidency, another thing mentioned by Russell T Davies to link in the events of the movie to the Time War and has Evelyn Smythe as a companion so despite being an audio and one-time book companion only, this would lead to at least some canonicity as well for The Marion Conspiracy. Since he outright mentioned one of the Dalek Empire audios as canon, this could also mean that the other three parts: The Genocide Machine, The Mutant Phase and The Time of the Daleks are as well, and if so - this would imply that the Fifth Doctor did indeed have travels on his own with Nyssa and the Eighth Doctor did have Charley Pollard as his companion, adding a degree of canonicity to all of his adventures with her.
If you map it out from this, it could turn out that much more of the Big Finish audios actually happened then you'd think. Infact, most of them. The question I put to you, faithful AP-DW fans then, is what outright cannot be canon?