(How crazy-cool is that story, by the way??)
Anyway, if you're familiar with Elizabeth Peters, you'll know what to expect of The Murders of Richard III: loads of mysterious hijinks while also being smart, funny, romantic, and entertaining. AND it has the added bonus of being one of the too-few Jacqueline Kirby books... she's a librarian with a Mary Poppins-ish handbag and martial arts know-how. In this one, she goes to a Ricardian weekend and a series of pranks TURNS DANGEROUS.
The Daughter of Time, meanwhile, is a bit more serious: it's one of Josephine Tey's far-too-few mysteries. In it, Inspector Alan Grant is laid up in the hospital with a broken leg, totally bored, and so his actress friend brings him pictures of historical figures who were embroiled in unsolved mysteries... and with the help of a young historian, he starts researching Richard III. It's seriously tragic that there are only, like, eight Tey mysteries—they are all totally, totally different and all totally, totally awesome. (My favorites, btw, are this one, The Franchise Affair, and BRAT FARRAR, which is OMG-FAINTWORTHY-SWOON-CENTRAL.)