The Council of Nicæa is a relatively short audio play in the Big Finish range, by Caroline Symcox (who I last saw at MeCon). It brings Peter Davison's Fifth Doctor, his TV companion Peri Brown and new audio companion Erimem to the year 325 and the theological disputes over the nature of God at the eponymous Council. Supporting characters from history are the Emperor Constantine, his wife Fausta, and the competing theologians Athanasius and Arius.
The Witch Hunters, by Steve Lyons, is an early one of the BBC's Past Doctor Adventures, set pretty firmly in TV chronology between The Sensorites and The Reign of Terror, bringing the First Doctor with companions Ian, Susan and Barbara to the village of Salem in Massachusetts in 1692, just in time for the infamous witch trials.
Both are stories in which there is no sfnal element in the historical context apart from the Doctor and his companions, and thus are very much rooted in the early traditions of the show. Both stories are a kind of response in Who terms to other writers - Symcox reacting against J. N. O. Kelly’s Early Christian Doctrines, Lyons more favourably to Arthur Miller's The Crucible. Both of them feature a historical context where, essentially, the bad guys are the mainstream authority Christians and the listener/reader is invited to sympathise with the underdog (Arius and his followers/the accused "witches"). In both cases, the youngest of the Tardis crew (Erimem/Susan) is instrumental in trying to change history in the favour of the underdogs, in both cases (and this is hardly a spoiler) unsuccessfully.
Symcox takes more liberties with the setting (Arius is portrayed as a young man and Athanasius as somewhat older; in fact the reverse was the case), as she is writing a more standard Doctor Who story and also has less time to do it in (less than 100 minutes, compared to Lyons' 282 pages). As often with Who, the Doctor gains the confidence of the authorities rather implausibly rapidly, which then of course accelerates the amount of trouble he and his friends get into. The two key elements of the story are the didactic part, informing the average listener who is (safely) assumed to know very little of the Council of Nicæa, and the character development of Erimem, who sides with Arius partly out of national solidarity (Arius was from Alexandria, Erimem is an ancient Egyptian princess) but more out of a sense of fair play. She pleads that because 325 is her future, she should not be accused of trying to change the past. It all worked rather well for me, certainly much better than The Church and the Crown, an earlier audio with a similar concept except that the Doctor intervenes to force history into our timeline.
Lyons makes the reader work harder; he has more characters to follow (not just four in the Tardis crew instead of three, but a large chunk of the population of Salem) and more background knowledge is assumed. He is also sticking closer to the historical sequence of events, though The Crucible is explicitly referenced, with the Doctor and crew taking in the first performance in Bristol in 1954, and the Doctor then returning with Rebecca Nurse to take it in again. Actually Lyons handles the possibility of changing history a bit less convincingly than Symcox, with even the Doctor rather un-Doctorishly seduced by the possibility of intervening to save lives. He also requires the Tardis to operate rather more accurately than we saw at this stage of the show's history. Balanced against this, there are a lot of pleasing references to the first few television stories. The narrative has its own drama, which carries the book in the end, but the Tardis crew rather end up with the roles of Rosencrantz and Guildenstern.
Anyway, I found it interesting to compare and contrast between the two approaches - same basic idea, but different format and different details.