A lot of good books in this thread - fascinating to see what people like!
Some of my personal favorites haven't been getting lots of love yet, so I'll speak up for the D's:
- Dorothy Dunnett -- esp. her Lymond of Crawford series - mid-16c Scotland, France & beyond, lots of adventure, a tortured hero (oh, yeah), and Grand Romance, all on a base of solid research & scintillating prose.
- Dumas pere -- the Three Musketeer series of course, but he also wrote a lot of other good books with different settings. For the 16c I rec. highly the pair of books featuring Chicot the Jester (La Dame de Monsoreau, sometimes called Chicot the Jester, and the Forty-Five) -- swashbuckling intrigue at the court of Henri III. There's also a good sequence set in the 18c, of which The Queen's Necklace is probably the best. Lots more, once you get started. Even his minor works are entertaining.
- Maurice Druon - the Accursed Kings series (starts with The Iron King). The schemes & misadventures of Philippe IV & his successors, from the destruction of the Templars to the Hundred Years War, lots of drama, adventure, tragedy, and compelling train-wrecks. (Highlights include the stage-managed election of Pope John XXII, when the cardinals were bricked into their church and voted in the oldest & sickest of them as a way to get out, only to find themselves stuck with him for another 20 hard years, and the overthrow & murder of Edward II by his wife & her lover. Ouch.) These have been OOP in English for a long time, but it's worth hunting them down. If you read French, they're all in print & available from Amazon.
Speaking of French, if anybody here does read French I've got a few more good recs, & wouldn't mind hearing more:
- Robert Merle, Fortune de France & its sequels -- a fascinating series set in the French Wars of Religion, written in 16c French. Yes, that's right. It's a bit challenging at first, but pretty quickly starts to sound natural. There were about 8 vols. at the time I was reading them, but he apparently picked the series up a few years later & continued with a bunch more into the 17c.
- Juliette Benzoni, Catherine et seq - romance & adventure in the 15c, with featured appearances by Jeanne d'Arc & Gilles de Rais (aka Bluebeard).
- Jean d'Aillon, The Investigations of Louis Fronsac - I've just discovered this series, which appears to be historical mysteries set mostly in the 1640s & 50s (aka one of my favorite periods). Unlike anybody else I've mentioned, he's still alive & actively writing. So yay!