Partly for research for the book after next and partly because I'll just enjoy reading it I'm going to buy some medieval history in the near future. It's slightly hard to decide what to go for, given there's tons of interesting, and highly rated, stuff on offer and my reading to date is pretty limited.
I think the only medieval history I've read, discounting a thin but memorable children's book about castles, is the Knight Unofficial Manual by Michael Prestwich and a Hawkwood biography by Stephen Cooper.
The aim for me is enjoyment as much as learning. I'm not going to be chained by history when writing, as one of the best parts about fantasy is the freedom it offers (not to mention Fenshire lynx and hornskins aren't actually real). However, a certain level of detail, often about the small things of life, can help make a fantasy world more credible and immersive.
Here are three recommendations I received from helpful fellows:
War in the Middle Ages, by Philippe Contamine - this is rather pricey at £28 (if I get it I'll probably use Abebooks for a second hand version, where it's less than half the price) but very highly rated.
Terry Jones' Medieval Lives - seems to be one of those books that blends fun with being surprisingly informative, not unlike the Unofficial Manuals series.
Montaillou: the Promised Land of Error, by Emmanuel le Roy Ladurie - is a book that's very well-regarded and revolves around life in a medieval village.
In addition to those books, I'm also looking at:
Life in a Medieval Village, by Frances Gies (not much point getting this and Montaillou, so I'll buy one or neither of them)
The Time Traveller's Guide to Medieval England, by Ian Mortimer (like Jones, this seems to be a light-hearted read)
By Sword and Fire: Cruelty and Atrocity in Medieval Warfare: The Savage Reality of Medieval Warfare, by Sean McGlynn (actually this was also recommended to me, quite some time ago, by an author renowned for his grisly depictions of woe and agony)
A Brief History of the Hundred Years' War, by Desmond Seward
Unfortunately I have quite limited space, as well as needing to get my head down and crack on with Journey to Altmortis, so I won't be buying all of the above. There's quite a bit of cross-over between various books so I'll see if there's a happily efficient way to cover the main areas (warfare, city life and so on) without having to bend the laws of time and space to accommodate the necessary books.
I've spent a little time fleshing out earliest sketches of characters and a rudimentary plot of book 1 for the trilogy, but I'm going to do the plot of all three books before I start the first draft of book 1. Michael J. Sullivan's Riyria Revelations were extremely coherent and well-integrated as a six story series, and his approach of sorting out the entire storyline before beginning worked very well, so I shall copy it.
However, in the nearer term I've been a little distracted and need to knuckle down and make more progress with the first redraft of Altmortis. After that, I'll probably write extra scenes (some of which are needed to correct glaring errors, like forgetting to properly finish off a certain character) and make various continuity changes before seeing where things stand. The world also needs a little work to make it more immersive, and I've got a few cunning ideas of how to achieve that.